> MorphOS 2.2 does not support multi-processing so the Cell processor
> is not very attractive to begin with.

Are you sure this is not only true for *symmetric* multi-processing, but also for *asymmetric* multi-processing (by using the SPEs)? Or do you refer to the 2-way SMT capable PPE rather than the SPEs?
The Friedens for example -- long before denying the reasonableness of OS4 port to PS3 -- once claimed that it would be technically possible to make use of the SPEs from within OS4 and OS4 programs and that they already thought out some rough technical concept on how that might be achievable. And AFAIK OS4 is actually exposed to the very same restrictions as MorphOS regarding multi-processing.