here are some relevant links:

number of transistors in 6502 and other classic processors
http://www.classiccmp.org/pipermail/cctalk/2001-May/170250.html

cell processors
http://cellsupercomputer.com/how_can_one_chip.php

number of transistors in modern intel processors
http://www.intel.com ...

I was thinking about this a few years ago, the 6502 has about 4000 transistors, while some modern CPUs (Itanium) have 1.72 billion transistors. So I think it would be possible to create a CPU containing thousands of 6502 cores, maybe 400,000 cores, and running faster than 1GHz speed. It would also ...