It heavily depends on the final design. I can go for a simple desing like CPS2 Multi or STV where you can have only one game at a time. That's the simplest and will cost about $350.I read through this entire thread the other night, and I may have missed it, but was a ballpark figure ever mentioned on what this may cost? I was thinking of just saving up around $500.00 and crossing fingers.
I can go also for a more complicated desing with FPGA+DIMMs so you can load many more games and it will be around $400+
I'm running tests right now....