When I think of insane customs, I think of cars like this.
This is the Sty-ray, a custom Corvette built in 1963 by Charles Gibilterra. It's one of the 150 historically important models that the International Model Car Builder's Museum wants to either locate and restore (if possible) or create a replica of for their collection.
To me, this is more indicative of customizing than simple bodykits like many of us do. I kind of would like to see some of the guys around here get involved with the IMCBM's Hot 150 program.