If your mspacman board is JAMMA, its a bootleg and probably no better than a 60 in 1. A 60 in 1 would also alleviate the need for a signal converter, but it does run a hacked version of MAME. Haruman also sells a pretty great Midway inspired cocktail cabinet if you dont want a bartop like the one pictured.
Why 4 buttons? a single coin and 2 start buttons would suffice, unless you go with the 60 in 1, then you need 3 action buttons (or just 2 if you dont play the one game that requires 3)