As I said a while back, if I ever do one, it will be on FPGA hardware.
I've ordered one of these - http://www.fpgaarcade.com/
several arcade games already converted for it, including SI, Frogger, Scramble, Phoenix, Crazy kong ... (although not galaxian, which I will do when I get my one if no-one else has already done it),
It should be possible to sort out a menu of some sort, and allow each game to return - and the guy (Mike) is planning to do a jamma connector for it, so once loaded up it will fit directly into your cabinet.
and as a sideline, you can play amiga, C64, Vic etc. games on it as well.
if someone does things like CPS1 or Neo Geo then it will have oodles of games immediately available! (and with the Amiga already there you could add the CD32 version of Parasol Stars)
ultimately it's the logical successor to Mame, since you can re-create the games at hardware level, so it should be possible for 100% identical functioning to real thing, and from the forum this one is building a reasonable following (although others do exist - I also have a Papilio)
I'm thinking that I'll end up with three of them - one in the cab, one under the TV (for consoles etc) and one by the computer for dev work & old computer emulation!