>> all I found was MorphOS 3.12 on an A1200/BlizzardPPC.

> Oh my! Post that! An updated MorphOS for Amiga Classic would be too cool.

The last PowerUP version I read of was MorphOS 3.8, and 3.10 was alluded to. So it's no surprise even later versions exist.

> there might even be cpus powerful enough to make that practical.
> I've seen a few that were clocked at 800 MHz.

1.0 GHz G4 is the fastest card successfully tested so far, I think.