yeah, it seems like im outta luck on the 'key+command' thing, but i found a work around for one of the command keys i was trying to get and that works great.
'screenshot' is also 'f12', so i just assigned that to one of my <shift> keys and now i can take screen shots from the stick, but now i need mame to have load newgame or 'command+o' to a single key, maybe even an 'f' key, that would rock.