I think if the new Amiga is to be a succsess i would suggest that just like when the first A1000 came out back in 1985, the new Amiga must be GROUND BREAKING, not just a machine which can run OS4 etc...
They should design a games console, but more powerful than the Playstation3 or Xbox360 with better processing power, better graphics hardware etc...
This is dreaming. Those hobby, few ppl, low budget wannabe companies in Amigaland don't even have remotely the resourses to do so.
My stance on how a ppc Amigaish computer would have a slight chance to sustain its business would be to do a low cost, low power uptake, tiny system.
A G4 1200-1500MHz compares in overall performance quite good to an Atom. The Freescale 8610 would be the ideal basis for such an effort. Woud probably be a bit more expensive than an Atom based design, but if done right, not several *magnitudes* more expensive. And for sure it wouldn't change the IT world, but I would be pretty confident, there would be a fair chance it sustainable on the market.
Unfortunately A-eon chose the expensive route and thus pretty much a dead end. Amiga today is today not about high end (defenitely not), but about hobby, liking all those little differences, preference or simply being used to (as long time Amiga user). Of course there are ppl willing to spend serious money for that, but probably not enough to sustain a business on it. By targetting the hobby crowd (say a new system in Atom/Mac mini G4 class for 250 EUR) I am sure quite some maschines could be sold.