Nintendo Vs. Unisystem was a series of arcade games put out by Nintendo in the 1980's. Similar to the Play Choice 10. But only having a single game per machine. There were some dedicated Vs. double cabinets produced which looked like 2 games butted together at an angle. A single motherboard powered both games on those models.
These games were designed primarily as a kit to retrofit Donkey Kong machines, and thus require the same special monitor that Donkey Kong did. Luckily a few different companies sell a little convertor that will allow you to use any standard open frame monitor in your game.
Almost all Vs. games were also released (with minor changes) on the Nintendo Entertainment System.
Vs. games could be quickly swapped to change the game in a cabinet. (Almost as easy as Jamma). Almost all Vs. games ran on identical hardware, and you can swap the game on any given boardset by burning a new program ROM and a new color PROM. This is a very affordable way to build up a pretty decent selection of titles. Of course it is technically illegal, but no one seems to go after people making home arcade hacks on 20 year old hardware. A Vs. multi-game would probably be fairly simple for any hardware wizard to implement.
Games on the Vs. Unisystem