> Yikes is PCI, Sawtooth is G4.

Both are G4, but Sawtooth is AGP ;-)

> Does MorphOS support later Sawtooth models, since they have AGP?

Yes, MorphOS runs on all PowerMac G4 models except the very first one (Yikes), with one caveat: onboard audio support starts only with the Digital Audio model (PowerMac3,4). Thus, MorphOS on Sawtooth and Gigabit Ethernet models requires a supported sound card (PCI, USB).