As noted in several places on the internet (Thread, Thread), there appears to be a PowerMac model listed in Mac OS X 10.3.4.
The new machine is listed as "PowerMac 8,1" and is found in the Info.plist file in the system's extensions directory.
This model was reportedly not found in Mac OS X 10.3.3.
Update: According to Appleinsider, the new PowerMac should be released by the end of June.
Top Rated Comments
I'd be impressed with this "rumor" if there were some details.