I'd do it the way I mentioned ages ago in another thread:
Arcade cabinets - for "official" (as in, Sega/Konami/Namco/SNK/Capcom,etc manufactured) cabinets. Either dedicated (an original Virtua Fighter 2 cab) or generic (a Blast City cab).
Motherboards - CPS2 A boards, MVS/PGM/Atomiswave motherboards and similar.
Games for motherboards - Any game that requires one of the above to run
Dedicated PCBs - Games that connect directly to the JAMMA/JVS/whatever wiring inside a cab and have no removable game, such as Soul Edge, Rodland, Strider, etc.
Sorry to sound like a broken record but I do think that'd be better than the current system.