I agree, lengthen the wheelbase, or could have a small box like the civi hummer truck.
Personally I'd consider an extended cab with lengthened frame and rear Axel taken back to match the stock bed fenders.
Never have I seen a picture though. Probably never been done, and with the age of these trucks I would only do it if I found scrap parts. I couldn't bastardize a classic.
I'd prefer a runner in poor cosmetic condition to a non-runner in a somewhat conveniently restorable cosmetic condition for the project. I'd go crew cab since I have two little ones that can't ride up front yet. Plus I have an extended cab now and I HATE that thing. Haha
There is one up this way, not done very well though. I'll see if I can find my pics. I know someone who has dreamed of doing a M37 crewcab for years.
I hope you find those pics. I'd LOVE to see that even poorly done. I wouldn't mind taking a crack at repairing someone else's mistakes (yes, I've done it a lot. I work in construction. Haha).
Go over to the Dodge Power Wagon site.
Some folks there have experience with doing crewcab on the flat fender - brother to the M37.
http://dodgepowerwagon.com/wwwboard/index.html
I looked at those, but the main thing about this is that the cab is completely different. I'd probably design my own cab with slightly back-swept windshield, but the curves of the Power Wagons match the hoods of the Power Wagons better, IMHO. I like the boxy MV simplicity. Thanks for all the replies.
I actually found a sweet deal on a runner AND mostly complete parts truck. Could've made a crew and had lots of spare parts saved for a rainy day. Too bad they guy sold the runner and wants $800 for the parts truck. That sounds like a decent deal, but I don't own a truck that needs any of those parts. Haha
The best I can do right now is hope the guy I talked to a while back will give me (since he "promised he wouldn't sell") the 37 below.