Horizontal or vertical? What kind of games do you want?
There is a 60-in-1 that is very common and has a lot of classics on it, and is vertical.
There is a JROK multi-Williams that is horizontal and has - what - 8-10 games on it?
There are some PC-based multi kits out there that 1000+ games on them, yet will work with a JAMMA harness. Some are vertical and some are horizontal.
I did a Blue Elf 2 conversion for a guy not long ago. 300+ games (mostly fighting games) and is horizontal...