One thing I don't have is a build environment that is able to process .i686 packages!

Actually as a side not I was wondering how different is environment which is being used to build .i386 packages from the .i686 one?  I usually only build the x86_64 ones and simply omit the .i686 ones which is not the best thing I could do but never actually got around to look up what is the actual difference?

At the moment I use mock 1.1.18 and its working a treat for i386 and x86_64 arches.