Have you seem these:
http://studiobergstrom.com/index.php?categoryID=74
http://studiobergstrom.com/index.php?categoryID=40
http://studiobergstrom.com/index.php?categoryID=83
http://studiobergstrom.com/index.php?categoryID=84
Some other company makes similar stuff.
Plenty of Space fleet rules out there, many with Star Wars mods/stats.
yes, not 'main stream', but then again space fleet gaming isn't main stream either.
In regards to X-Wing, it is supposed to have different mechanics than Wings of War, but will have similarities. I'm not sure why you couldn't repaint the ships as you see fit. Lots of folks repaint prepainted figures.
Future War Commander is a 'epic scale' ground combat game. I know there are Star Wars stats for it.
There are 15mm Star Wars minis if you look for them. Someone recently released a Han Solo, Boba Fett and Chewie for example. Plenty of 15mm troops could be used as both rebels and empire forces...