> the x800Pro is listed in http://morphos.de/hardware

Yes, but it doesn't say an X800 Pro with x86 ROM will work in a PPC Mac, does it?

> the X800XT, which was recommended in the present thread, is not R500-based.

At that point the discussion wasn't about x86 ROM graphics cards. The X800XT with PPC ROM will work in a G5 Mac, of course.