There was already the Game Brains project that allowed different Z80 based games to be played on the same console... But what about a universal game console that played all kinds of 8 bit systems; CPU independent. This sounds like a nightmare with glue logic but what about a FPGA? It should be flexible enough to handle any new system that you want to ad to it.
Of course, this might have already mentioned by others. But it seems with the recent FPGA videos this might be a natural progression.