Recently I was made aware of something called Call of Duty 4: Galactic Warfare, which is a mod for cod4 in which everything looks like star wars. As far as i'm concerned, there is only the Empire and rebels as factions but each have the 5 or so classes and there are only two maps.
All things considered this is a purely aesthetic change but it's a damn good one!
heres a trailer:
http://www.youtube.com/watch?v=A3tasgo0KY8