If Ubuntu can be installed, then we have to worry about the limited local storage.
And yes, any new PPC board would probably be several times the cost of this.

But, it would not involve an ISA change.

And even so, I will probably find myself buying something ARM based eventually.

I'm not sure why. As I've mentioned, I have 1.6 and 1.8 dual core Atom based netbooks which are probably just as capable (and cost me less). And I know I could run Ubuntu on both of those as they both have hard drives.

Curiousity I guess.
And still, compared to ARM, I'd rather have a PPC (for now, and the near future).