Sounds like he wants to take a skin from an LFS car and actually put it on his real car. You're talking about the opposite (taking a skin from a real racing car and making a version you can use in LFS).
I was trying to be sarcastic, but it failed i guess. I mean whats the difference between an "LFS" skin/paint-job/livery and a real car that has been painted.
Or like 5tag said, using a 1024px skin, print it out and slap on a real car?