Just an opinionated old fart, but I just don't see any real "upgrade" with that.  Marginally better torque and no doubt much better mileage, but less drivable for most uses.

I have had 4 Benz diesels over the years, starting with a 190Db, then a 240D, followed by a 300SD (617 turbo), and the last a 300CD (also 617 turbo).  Each and every one was a royal pain in the posterior when temps got below zero F.  The non-turbo 190 and 240 D were totally gutless and I well remember being in 2nd gear on I70 in CO trying to keep 20 mph while everyone is zooming by at 75 mph and watching my butt hoping not to have to hit the ditch to keep from getting a plastic/metal enema.  The 617 turbos were WAY better, but with a highly significant turbo lag that caused a big drivability issue.  However, once spooled up, those engines have enough torque to do just about anything, including going over both I70 and I90 passes at 75 mph.

For less money-probably a lot less money, there could be a small block Chevy under there, custom built to suit your driving style and needs, something that has two to three times the torque and gets 50% better mileage than the L head.  If you are going to hack it anyway, I just can't see that the tractor motor has any real merit.

I dig it. Course I'm biased since I'm putting a diesel in my MB. There is a guy in the willys section on pirate4x4 building a flatty with this motor.

Definitely something I'd consider doing. It would be nice to be able to burn used motor oil as fuel.

Why do you say that? A mechanically injected engine will burn oil. Even the TDI motors can have "runaway" from a blown turbo seal sending oil into the cylinders and the motor will keep running even when the fuel is shutoff.