I think I've found a use for one of the engines that will kill two birds with one stone. Came across a '95 GMC Sierra 2500 with the NV4500 for a good deal, it has a 350 (TBI, gutless really), NP241 t-case (?) and a semi-float 14 Bolt. It has the same updated (for a '95) body style and interior of the '98 GMC Sierra that I built awhile ago. I like that body style and look.
I'm thinking about picking up the truck as a tow rig and eventually swapping the Isuzu 4BD1T into it, with a larger turbo and run a Dodge intercooler. That setup should be good for 400+ ft/lbs and 25 MPG w/o a load. I would imagine it would still pull down around 20 MPG towing a trailer, which is damn respectable. Really will depend on gear ratio, average MPH & RPM's, etc. Still, low-buck diesel tow rig that is simple, reliable, built with quality components... should ride good, be cheap to insure and last a long time. It would be nice to upgrade the interior & seats with something newer/better. Factory leather bucket seats from a newer GM truck would be great.