If Ms. Pac Man is JAMMA, you should be able to unplug your MVS unit from the JAMMA harness and plug in the Ms. Pac Man PCB. I use an HGA though, and don't know how dedicated MVS cabinets work, but I assume how the MVS connects is the same way.
As for an actual Ms. Pac Man MVS cart, I doubt you'll find one, unless someone made a hacked version for whatever reason like Nick said.