I just got my Butler Racing custom aluminum seat installed by Bender Race cars. Seat took a little while to get from Butler but it was custom made and because of a little longer than expected wait they threw on high density seat padding on for no charge. My seat was installed perfectly the way I want it and he had it done in a few hours.
I will be going back to have bumper brackets made, cage finished out, and a few other things. They do tubs, cages, exhaust, and just about anything involving metal.
614-252-7223
Here's a pic of my seat...
http://i8.photobucket.com/albums/a20/ZeroBar78/Seat2.jpg