I remember the developer said (on the MorphOS ML) that 2D for that GFX card was working just fine - just no 3D. As far as booting the PowerBook from the MorphOS v2.4 CD goes, I seem to remember him saying it shouldn't be that much trouble (I might be wrong, too bad I lost most of my MorphOS ML with a stupid action from myself - if someone does a search on 'PowerBook' or 'wlamee' in the MOS ML, it should come up as an answer on one of my last mails).
If I try to boot the PowerBook G4 from the MorphOS v2.4 CD, I get a grey screen with two lines of text, 'Quark/OpenFirmware' and '_'. After that nothing happens. If someone (maybe the MOS developers?) can get me any further on this, I would greatly appreciate it (and buy another MOS license, of course).