It's unclear if you want reports of things *working* and if so how to report them. With that proviso, perhaps you want to stop reading here and delete this "bug" report.... Anyway, after reading one of the recent Gentoo newsletters I decided to try Module X on a newly installed PPC. I have fluxbox running now. Seems quite OK and was not too hard to install using the migration guide (although they forgot to mention you should put x11-base/xorg-x11 in your keywords file, they have fixed that now). So, good news! I will continue trying to break stuff now.
It's already keyworded ~ppc; will move to stable soon (we'll have a stabilization bug for that). Thanks for the report anyway. ;)