I actually toyed around a bit with the idea of Atari boards. The issue I kept coming up against was that I just couldn't totally nail down the full schematic on them for the CPU board. The atari style schematics are a disjointed mess, and there's some oddball stuff to the clocking circuit on Atari's where it changes processing speeds on the fly. That, and I don't know if I could hit the magic 50 board number to get it to break even financially. At least in a Superman, you could make the boards smaller, which would save a good amount of overall cost. There's a lot of wasted space on those boards, such as the extra half dozen prom sockets that are never used.
I'll have to ping one of my Atari contacts again about the concept, he may be able to give me a nudge to figure it out better.
Displays for Superman wouldn't be too hard to do though. I'd just need to get my hands on one for the dimensions and such. Selling about 12 sets would be the break even point on them I think.
-Hans