As far as I could tell they were running a MAME frontend (I have seen it before, but can't remember which one). I THINK those were the cabinets with the note that said more games could be added, but there were so many 39 - in - 1's and other multigame cabs there, I can't remember for sure. They were cool looking. If I had the templete, I'd build the kids one...
Jay