NES Expansion port

[c64kid]

This is a really dumb idea but I was thinking that maybe if you could have some sort of peripheral that would allow you to play atari 2600 games on your nes using the expansion port. I was thinking maybe the accessory would contain the actual internals of an atari and maybe through some clever coding I could make the cpu in the nes communicate with the internals of the atari. I would also probably use the controller ports offered by the nes expansion port for something. for the audio I could use the audio in pin.