SS, if you need a connector with a lot of pins, go for a card-edge connector. Basically what the n64 and most cartridges use. Heck, use an n64 cart slot and cart bottom.
Also, see the new LOB64 standard. I did some testing, and you need to have the slave and master N64's on at the same time. So, just don't add a switch to turn the N64 off.