Alright ... I think I got it...
What I did from the beginning:
This site:
https://wiki.debian.org/Multiarch/HOWTO suggests to make /etc/apt/sources.list support multiarch by adding [arch=amd64,i386] to the deb-line. e.g.:
deb [arch=amd64,i386]
http://de.archive.ubuntu.com/ubuntu/ saucy universe
Next I added the PPA again (because I need the newest Version of wine) and took care that dpkg recognizes i386.
sudo add-apt-repository ppa:ubuntu-wine/ppa
sudo dpkg --add-architecture i386
sudo apt-get update
Update of the database now showed separate amd64 and i386 repos to be loaded.
Next I switched to aptitude, because of the more sophisticated dependency-solver:
sudo aptitude --full-resolver -f install wine1.7
The following NEW packages will be installed:
binfmt-support{a} fonts-horai-umefont{a} fonts-unfonts-core{a} gnome-exe-thumbnailer{a} icoutils{a} imagemagick{a} imagemagick-common{a} libasn1-8-heimdal:i386{a} libasound2:i386{a}
libasound2-plugins:i386{a} libasyncns0:i386{a} libavahi-client3:i386{a} libavahi-common-data:i386{a} libavahi-common3:i386{a} libcapi20-3{a} libcapi20-3:i386{a} libcomerr2:i386{a}
libcups2:i386{a} libdb5.1:i386{a} libdbus-1-3:i386{a} libexif12:i386{a} libflac8:i386{a} libfontconfig1:i386{a} libfreetype6:i386{a} libgcrypt11:i386{a} libgd3:i386{a} libgif4{a}
libgif4:i386{a} libglib2.0-0:i386{a} libglu1-mesa:i386{a} libgnutls26:i386{a} libgpg-error0:i386{a} libgphoto2-6:i386{a} libgphoto2-port10:i386{a} libgpm2:i386{a}
libgssapi-krb5-2:i386{a} libgssapi3-heimdal:i386{a} libgstreamer-plugins-base0.10-0:i386{a} libgstreamer0.10-0:i386{a} libhcrypto4-heimdal:i386{a} libheimbase1-heimdal:i386{a}
libheimntlm0-heimdal:i386{a} libhx509-5-heimdal:i386{a} libice6:i386{a} libieee1284-3:i386{a} libjack-jackd2-0:i386{a} libjbig0:i386{a} libjpeg-turbo8:i386{a} libjpeg8:i386{a}
libjson-c2:i386{a} libk5crypto3:i386{a} libkeyutils1:i386{a} libkrb5-26-heimdal:i386{a} libkrb5-3:i386{a} libkrb5support0:i386{a} liblcms2-2:i386{a} libldap-2.4-2:i386{a}
liblqr-1-0{a} libltdl7:i386{a} liblzma5:i386{a} libmagickcore5{a} libmagickcore5-extra{a} libmagickwand5{a} libmpg123-0:i386{a} libncurses5:i386{a} libnetpbm10{a} libodbc1{a}
libogg0:i386{a} libopenal1:i386{a} liborc-0.4-0:i386{a} libosmesa6{a} libosmesa6:i386{a} libp11-kit0:i386{a} libpcre3:i386{a} libpng12-0:i386{a} libpulse0:i386{a}
libroken18-heimdal:i386{a} libsamplerate0:i386{a} libsane:i386{a} libsasl2-2:i386{a} libsasl2-modules:i386{a} libsasl2-modules-db:i386{a} libselinux1:i386{a} libsm6:i386{a}
libsndfile1:i386{a} libspeexdsp1:i386{a} libsqlite3-0:i386{a} libssl1.0.0:i386{a} libtasn1-3:i386{a} libtiff5:i386{a} libtinfo5:i386{a} libudev1:i386{ab} libusb-1.0-0:i386{a}
libuuid1:i386{a} libv4l-0:i386{a} libv4lconvert0:i386{a} libvorbis0a:i386{a} libvorbisenc2:i386{a} libvpx1:i386{a} libwind0-heimdal:i386{a} libwrap0:i386{a} libxcomposite1:i386{a}
libxcursor1:i386{a} libxi6:i386{a} libxinerama1:i386{a} libxml2:i386{a} libxpm4:i386{a} libxrandr2:i386{a} libxrender1:i386{a} libxslt1.1:i386{a} libxt6:i386{a} netpbm{a} odbcinst{a}
odbcinst1debian2{a} unixodbc{a} winbind{a} wine-gecko2.24{a} wine-gecko2.24:i386{a} wine-mono0.0.8{a} wine1.7 wine1.7-amd64{a} wine1.7-i386:i386{a} winetricks{a}
0 packages upgraded, 123 newly installed, 0 to remove and 0 not upgraded.
Need to get 200 MB of archives. After unpacking 557 MB will be used.
The following packages have unmet dependencies:
libudev1 : Breaks: libudev1:i386 (!= 204-0ubuntu19) but 204-0ubuntu18 is to be installed.
libudev1:i386 : Breaks: libudev1 (!= 204-0ubuntu18) but 204-0ubuntu19 is installed.
The following actions will resolve these dependencies:
Keep the following packages at their current version:
1) libgphoto2-6:i386 [Not Installed]
2) libgphoto2-port10:i386 [Not Installed]
3) libsane:i386 [Not Installed]
4) libudev1:i386 [Not Installed]
5) libusb-1.0-0:i386 [Not Installed]
6) wine1.7 [Not Installed]
7) wine1.7-amd64 [Not Installed]

wine1.7-i386:i386 [Not Installed]
Leave the following dependencies unresolved:
9) winetricks recommends wine1.5 | wine1.4 | wine | cxoffice5 | cxgames5
10) wine-gecko2.24 recommends wine1.5-amd64
11) wine1.7-i386:i386 recommends libsane:i386
12) wine-gecko2.24:i386 recommends wine1.5-i386:i386
Accept this solution? [Y/n/q/?] 6
Action "6": Removing wine1.7
Package: wine1.7
New: yes
State: not installed; will be installed automatically
Multi-Arch: allowed
Version: 1.7.4-0ubuntu4~saucy1
Priority: optional
Section: otherosfs
Maintainer: Scott Ritchie <scottritchie@ubuntu.com>
Architecture: amd64
Uncompressed Size: 6.255 k
Depends: debconf (>= 0.5) | debconf-2.0, libc6 (>= 2.17), libgettextpo0, wine1.7-amd64 (= 1.7.4-0ubuntu4~saucy1), binfmt-support (>= 1.1.2), procps, wine1.7-i386 (= 1.7.4-0ubuntu4~saucy1)
PreDepends: dpkg (>= 1.15.7.2~)
Recommends: cups-bsd, gnome-exe-thumbnailer | kde-runtime, fonts-droid, fonts-liberation, ttf-mscorefonts-installer, fonts-horai-umefont, fonts-unfonts-core, ttf-wqy-microhei, winbind,
winetricks, xdg-utils
Suggests: dosbox:any
Conflicts: wine1.0, wine1.0, wine1.2, wine1.2, wine1.3, wine1.3, wine1.4, wine1.4, wine1.7
Replaces: wine, wine, wine1.0, wine1.0, wine1.2, wine1.2, wine1.3, wine1.3, wine1.4, wine1.4, wine1.5, wine1.5, wine1.6, wine1.6
Provides: wine, wine1.7:any
Description: Microsoft Windows Compatibility Layer (Binary Emulator and Library)
Wine is a compatibility layer for running Windows applications on Linux. Applications are run at full speed without the need of cpu emulation. Wine does not require Microsoft Windows,
however it can use native system dll files in place of its own if they are available.
This package includes a program loader for running unmodified Windows executables as well as the Wine project's free version of the Windows API for running programs ported from Windows.
This action was selected because wine1.7 depends upon wine1.7-i386 (= 1.7.4-0ubuntu4~saucy1).
Enter "r 6" to prevent this action from appearing in new solutions.
Enter "a 6" to require that new solutions include this action if possible.
Accept this solution? [Y/n/q/?] r 6
Rejecting the removal of wine1.7
The following actions will resolve these dependencies:
Keep the following packages at their current version:
1) libgphoto2-6:i386 [Not Installed]
2) libgphoto2-port10:i386 [Not Installed]
3) libsane:i386 [Not Installed]
4) libudev1:i386 [Not Installed]
5) libusb-1.0-0:i386 [Not Installed]
6) R wine1.7 [Not Installed]
7) wine1.7-amd64 [Not Installed]

wine1.7-i386:i386 [Not Installed]
Leave the following dependencies unresolved:
9) winetricks recommends wine1.5 | wine1.4 | wine | cxoffice5 | cxgames5
10) wine-gecko2.24 recommends wine1.5-amd64
11) wine1.7-i386:i386 recommends libsane:i386
12) wine-gecko2.24:i386 recommends wine1.5-i386:i386
Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:
Downgrade the following packages:
1) libudev1 [204-0ubuntu19 (now) -> 204-0ubuntu18 (saucy)]
2) udev [204-0ubuntu19 (now) -> 204-0ubuntu18 (saucy)]
Accept this solution? [Y/n/q/?] Y
The following packages will be DOWNGRADED:
libudev1 udev
The following NEW packages will be installed:
binfmt-support{a} fonts-horai-umefont{a} fonts-unfonts-core{a} gnome-exe-thumbnailer{a} icoutils{a} imagemagick{a} imagemagick-common{a} libasn1-8-heimdal:i386{a} libasound2:i386{a}
libasound2-plugins:i386{a} libasyncns0:i386{a} libavahi-client3:i386{a} libavahi-common-data:i386{a} libavahi-common3:i386{a} libcapi20-3{a} libcapi20-3:i386{a} libcomerr2:i386{a}
libcups2:i386{a} libdb5.1:i386{a} libdbus-1-3:i386{a} libexif12:i386{a} libflac8:i386{a} libfontconfig1:i386{a} libfreetype6:i386{a} libgcrypt11:i386{a} libgd3:i386{a} libgif4{a}
libgif4:i386{a} libglib2.0-0:i386{a} libglu1-mesa:i386{a} libgnutls26:i386{a} libgpg-error0:i386{a} libgphoto2-6:i386{a} libgphoto2-port10:i386{a} libgpm2:i386{a}
libgssapi-krb5-2:i386{a} libgssapi3-heimdal:i386{a} libgstreamer-plugins-base0.10-0:i386{a} libgstreamer0.10-0:i386{a} libhcrypto4-heimdal:i386{a} libheimbase1-heimdal:i386{a}
libheimntlm0-heimdal:i386{a} libhx509-5-heimdal:i386{a} libice6:i386{a} libieee1284-3:i386{a} libjack-jackd2-0:i386{a} libjbig0:i386{a} libjpeg-turbo8:i386{a} libjpeg8:i386{a}
libjson-c2:i386{a} libk5crypto3:i386{a} libkeyutils1:i386{a} libkrb5-26-heimdal:i386{a} libkrb5-3:i386{a} libkrb5support0:i386{a} liblcms2-2:i386{a} libldap-2.4-2:i386{a}
liblqr-1-0{a} libltdl7:i386{a} liblzma5:i386{a} libmagickcore5{a} libmagickcore5-extra{a} libmagickwand5{a} libmpg123-0:i386{a} libncurses5:i386{a} libnetpbm10{a} libodbc1{a}
libogg0:i386{a} libopenal1:i386{a} liborc-0.4-0:i386{a} libosmesa6{a} libosmesa6:i386{a} libp11-kit0:i386{a} libpcre3:i386{a} libpng12-0:i386{a} libpulse0:i386{a}
libroken18-heimdal:i386{a} libsamplerate0:i386{a} libsane:i386{a} libsasl2-2:i386{a} libsasl2-modules:i386{a} libsasl2-modules-db:i386{a} libselinux1:i386{a} libsm6:i386{a}
libsndfile1:i386{a} libspeexdsp1:i386{a} libsqlite3-0:i386{a} libssl1.0.0:i386{a} libtasn1-3:i386{a} libtiff5:i386{a} libtinfo5:i386{a} libudev1:i386{a} libusb-1.0-0:i386{a}
libuuid1:i386{a} libv4l-0:i386{a} libv4lconvert0:i386{a} libvorbis0a:i386{a} libvorbisenc2:i386{a} libvpx1:i386{a} libwind0-heimdal:i386{a} libwrap0:i386{a} libxcomposite1:i386{a}
libxcursor1:i386{a} libxi6:i386{a} libxinerama1:i386{a} libxml2:i386{a} libxpm4:i386{a} libxrandr2:i386{a} libxrender1:i386{a} libxslt1.1:i386{a} libxt6:i386{a} netpbm{a} odbcinst{a}
odbcinst1debian2{a} unixodbc{a} winbind{a} wine-gecko2.24{a} wine-gecko2.24:i386{a} wine-mono0.0.8{a} wine1.7 wine1.7-amd64{a} wine1.7-i386:i386{a} winetricks{a}
0 packages upgraded, 123 newly installed, 2 downgraded, 0 to remove and 0 not upgraded.
Need to get 201 MB of archives. After unpacking 557 MB will be used.
Do you want to continue? [Y/n/?] Y
Get: 1
http://de.archive.ubuntu.com/ubuntu/ saucy/main libgpg-error0 i386 1.12-0.2 [12,5 kB]
Get: 2
http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu/ saucy/main wine-gecko2.24 amd64 2.24-0ubuntu1~ppa1 [23,5 MB]
...
############ The usual Stuff goes here ... ############
What I did in short:
- aptitude suggested a solution where wine1.7 would not be installed
- This solution was rejected with 'r 6'
- The new suggestion was to downgrade both libudev1 and udev by one version (All dependencies met!)
- i did that! AND: it works!