Here's some pics of the work along the way with some descriptions: http://imgur.com/a/bvSgi
Here's a video of it in action too: http://www.youtube.com/watch?v=uWyzav0W198
The short version is I took a famicom converter from a copy of gyromite and wired it up to the NES 72-pin connector, and then mounted it on there too so it's all one removable unit. I carefully cut out a cart slot on top and used some dust covers from a dead N64 that I trimmed up to fit. While I was at it I also trimmed back the NES 72-pin connector and soldered a new regular card edge style connector onto it (I used this one: http://www.digikey.com/product-detail/e ... -ND/770547). I'm pondering adding a DB15 port so Famicom accessories can be used, but I don't currently own any so I'm in no rush (and I can't think of a good aesthetically pleasing please to mount it).
I think it all worked out pretty well and now I'm just waiting on the RGB board so I can install it