Well, Thats about all I know to check without putting the car on a jig or lift and pulling a tape measure to all the alignment points.
Don't rule out the front coil springs yet. Can you see the end of the coil by looking through the tiny inspection hole in the lower control arm? If yes, and all the bushings, springs, etc are all double checked it may be time to have a frame/body shop check it.
Keep us posted. It's driving me nuts too. :?