Thanks very much guys, helpful replies as usual.
The Mac clone I'm running is a 604/132.
I never tried PPC myself but it should work on that machine. The software is limited but these days it's hobby developers and porting should consist of a re-compile. You could ask some devs if they'd be willing to do a port.
Right, first off, OpenBeOS isn't out yet in any shape or form, and even though its progress is good, its still probably 7 years away from being where the original R5 was in terms of functionality.
I doubt given their progress it'll take anywhere near that long, I'd say a couple more years maybe for a full release. They are not developing a new OS, it's based on an existing one and that saves a lot of time.
Zeta is X86 only as ppc support was officially dropped with R5pro.
There's more than a distict possibility of a Pegasos port of Zeta, Genesi and Yellowtab have already had discussions about it.