also, one other thing. if you want a standard width dually, you have to use a STD dually axle. if you want a standard utility bed, you might be able to use a stock axle. i know Chevy(im new to dodge) had 3 widths of axles. chassi cab dually was narrower, stand SRW and dually. im not sure how dodge does it, but you could take measurements to figure out what it is you want. me personaly, i want the dually for towing stability with my 21k ooseneck. so i will be using a STD dually axle to widen up as much as possible, and then making the flat bed wider, or like said beofre using the dually fenders and some glass work if needed.
Grant