It may never happen.
I would not encourage others to buy hardware in anticipation of a port of MorphOS that has not been announced.

I just had a chance to buy the best G5 Apple produced and the price was good so I went for it.
And I already had an Apple Radeon X1900GT video card on hand, so now I can make use of it.

Also I just plain like PPC based systems.
I intend to buy a P5040 X5000 when it is introduced.
So if I cannot compare MorphOS benchmarks, I will be able to compare the systems running Linux.