There was a fellow bolter (from Minnesota I think) that extended his cab. He posted pictures too. He cut the cab and lengthened the doors. It gave it a nice chopped look without changing the head room height.
Sounds like you are looking for a crew cab. I know a couple of years ago there was a custom 4 door at the Truck Nationals. Try this link. I think there is a picture of it here.
http://s160.photobucket.com/albums/t172/stovebltr/
