"BTW, Nvidia only supports pre-compiled drivers for Linux, right? Does anyone know if they support the PPC?"
no, they don't
there was some time ago a web with a petition to nVidia to release PPC versions for linux but I can't remember the URL...
BTW Radeons work quite well, are cheap and fast, the Amiga/MorphOS native drivers will probably work quite well, you can buy one in any pc shop... well, I can't see the point in trying to support undocumented hardware that gets hot too fast when you can have full support and documentation for Radeons (and the run a bit cooler).
