In an attempt to skin it down even further I went with Vantage. Thanks to general Zod I was able to get the entire system up and running with arcadeos in under 20MB of space. I'm amazed

the OS, all the drivers, roms, programs and utilities in under 20MB of space. I may do as civic83 suggested and put the entire hard drive on a flash card and use that as my primary storage. This is so cool!
Fortunately the bartop that this will go into was only supposed to have frogger, galaga, pacman,ms pacman and a few others--thats it-- so vantage was the perfect solution--anyone know if some other roms can be made to work with it?