There is someone who makes a steel box that mounts in the front of the bed, and you take your original tank out of the cab and put it in the box. There is a flip top lid to fill the tank. It takes up about 8" in the front of the bed and is flush with the header panel of the bed. I'll look through my catalogs to see if I can find it and will post a follow up msg with the name of the place.

Chris Seay
Bealeton, VA