Would be a good 'second best' to porting for x86...
...I suspect no more likely for the same reason:
OS4 on PPC is about control of the platform & potential user-base (
). If it ran on widespread hardware that control would be lost.
Mind you - OS4 on x86 would require the sources (a job for Hyperion) but OS4 on PPC-Mac may
be feasible as a 'home project'...
...it would be a hell of a lot of work for an independent coder.