OK, progress update.
The cab's previous JAMMA wiring (done custom for the multiboard) has been removed. I also removed the panel, which was quite honestly cheaply made out of some plywood and a plastic overlay in a short period of time. The arcade stick was a standard 6-button fighter layout, and I've replaced it temporarily with an X-Arcade, though I'll replace it with a new panel and Ultrastick 360s when I get the money/time.

(I apoligize for the bad quality of the picture, I can't get good lighting down in my "game room" (designated area in basement with rug & Apple IIs) and, as such, I will not have many more pictures)
For now, I've installed GroovyGameGear's CLASSX pushbuttons with Micro-Leaf switches, which resemble a quiet miniature microswitch with a leaf to have better actuation, which feel very similar to a leafswitch, hence the name. The buttons are quite nice, though slightly smaller than those in an average cabinet, and with slightly more of an edge, which I actually like more than standard buttons. I have also replaced all of the joystick switches with VersaMicro switches for them to be quieter, which actually feels quite nice, though it feels like it is harder than it should be to do things like perform Hadokens and pull off combos, which is one of the reasons I will eventually purchase a Ultrastick 360 to use in my cabinet.
I've added in a Mac Mini (size constraint, running Windows 7) into the coin bucket area to have easy access to it, and also to have access to the power button when I want to turn the machine on.
I would like to re-add a CRT back into this thing, since right now it has a 16:9 LCD, but I don't have any original chassis, so I would have to make one, which is tough to do to say the least.
Much more to come.