Hi,AFAIK installation of skype-debian_4.1.0.20-1_i386.deb on Wheezy with multiarch is also impossible because some of the i386 libraries are of different versions:
package-0:i386 1.2.49-1 cannot be configured because libpng12-0:amd64 is at a different version (1.2.49-3)
Hugo