I wouldn't go the a500 way, because it is very expensive to get it to the max. Not too long ago, a person from this forum bought an accelerator for the 500 that cost him 400 eur. I think it was the 040 one. Is too much money and for that amount you could get an a1200 with accel and better performance.
On the other hand, an a500 with the never sold ppc board would be uber cool. I saw a photo of it and it was impressive!.
