Yes I know about them: neogeo, stv, megaplay, playch10
Emu Loader does support multi-slot loading for these systems already
Even though playch10 (PlayChoice-10) doesn't have support for multi-slot loading, I've included it in the IsMultiSlotArcade() function I've created for Emu Loader.
This function will check for all arcade machine names with multi-slot loading support.
Ciro Alfredo Consentino
EmuCon Home: http://emuloader.mameworld.info/emucon
MCM Plus: http://mcm.mameworld.info