What factors could affect wheel offset (besides the wheels themselves, obviously). I ask because my front right wheel sticks out about 12mm more than the front left wheel.

The driver side wheel is tucked under the fender by a few mm, while the passenger side wheel is sticking out past the fender by a few mm. Any ideas?

 

camber+one side is probably lower than the other

 

Height and camber are the same on both sides (I have a camber kit).

 

Has the car ever been hit? Sounds like something is bent/shifted. Probably bent. I'd start measuring suspention pieces and see if you can find anything. Check the subframe too.