I´m gonna get branded, tarred and feathered for it, but maybe Legends of the Old West would be nice - you´d only have to write up rules for automatic weapons and vehicles (the latter, IMHO, mainly require rules for blowing up...).
LOTOW is very quick and cinematic, IMHO. Unless you put some work into writing up a points system, however, you´ll have to do some careful balancing for scenarios.