Re: 95 2500 TD
Class 4 to 8 trucks, and a few 3's, are sold cab and chassis only. Now as to what kind of bed? The only limit is your imagination and dollars. I have seen class 6 GM's, Frieghtliner's, Ford's, Navistar, all with pickup beds on them. But they were custom added with mucho expense. Basically you wold have to shorten/lengthen the chassis to match the CA (cab to axle) length of a pick up with the bed you wish to put on. There are flatbeds, RV trailer towing beds with mutiple storage compartments, wrecker bodies, the list goes on and on.
If you want a single wheel, you would have to find rims to match the bolt pattern, remove the front extension hub for the dually option, not to mention a number of other things.
Look up The Turtle Expidition on line or thru 4 Wheelers on line web page. They took an F-550 and converted it to a SW multifuction go any where camper. Other than being the brand it is, it's pretty cool. There is a multi picture article on how they did conversion etc.
So anything can be done with one of these, even convert 4x2's into 4x4's. How much money do you have?