So what you are saying is that you want something like whatever the crap it's called you just don't want whatever the crap it's called. Hasn't this been done already with the three MM pins that were built from scratch (yeah, yeah I know the first one had a donor machine). I am pretty sure you can find nearly all of the parts for one of the more established W/B titles. So, why don't you just go that route? Sure you would have to build the wiring harness and that would be a pita, but the schematics are out there; so, not an impossible task.
I dig your idea and I understand that it would save a lot of the hassle for someone to sell this as a kit, but rounding up all of the parts yourself does not seem like it should be an idea killer to me. Especially given the grand scope of a project like this.