Since I'm 99% sure the XCL will be my next frame I might as well put in my 2 cents.
I totally agree with the ball burnished rear sections. They look great and don't get all chipped and scratched.
As far as colors, I really don't have a problem with any of the current offerings, but as others have said, a blue would look nice. Maybe something to match the blue bits on the Fox shocks.
I also think a cream or dark green metallic would look good. My original full suspension (way back) was an Amp B3 with a dark metallic green front and polished rear. It was really sharp.