There is also a discrete-transistor version that runs much slower than the original 6502, but with the advantage of an LED on each signal, so you can watch it run.

https://m.youtube.com/watch?v=tQIwS2GzXLI

See also (not a 6502 though)

http://6502.org/users/dieter/mt15/mt15.htm

that approches half as fast as a real 6502.