The second cab I ever bought was a Surf Planet -- I bought it because it came in a nice Capcom Big Blue with a beautiful monitor that I thought would be perfect for a 2-player MAME.

I had planned on selling the Surf Planet bits, but once the kids played it and we got in a competitive groove, there was no way they were going to let me sell it.
So, my Big Blue MultiJAMMA cab was born -- I moved the analog stick to the upper right and dropped in a standard SF-6/trackball layout, threw in a GT2K board and whatever other JAMMA board I wanted for the 8-ways and buttons.
It is far from awesome sauce as a game, but it's easy to play (only the side-to-side analog stick) and tough to master (shaving fractions of a second off of a run to get back on the high score board can take hours).
YMMV