I wanted to get the gas tank out of the cab for safety reasons and to eliminate the smell . So I got a universal tank from Tanks and had it powder coated chrome. It comes with the straps, pickup-up tube, cap and a nice trim ring to fit into the bed wood. I did have to fab the upper pieces running across the top of the tank between to frame crossmembers. This gives the straps something to pull up against and insured that the bed cross sills would stiil work without any mods.
http://www.tanksinc.com/index.cfm