This is an old post, preserved for reference.
The products and services mentioned within are no longer available.
A while ago, I built some 6502 ROM and RAM placement boards to use on 6502 based computers such as the Commodore PET and VIC20. I have since been contact by a few people who were also after these boards, so I used up the few spares boards I had originally made up.
V3.1 boards. These have an additional LED, which I have set to show activity, currently on for reading, off for writing, but I may also look at on for ROM access, off for RAM access etc.
2022 Update: This redesigned small version of the PET ROM/RAM boards are still available from TFW8b.com