What about a retired Uhaul 26' box truck? It runs a 7.3 N/A IDI but once you pull the box, shorten up the frame, and possibly add a sleeper, you'll have a MDT that'll pull 10K lb all day long. If you don't like that route, there's plenty of MDT's out there in the DT466 variety that'll also accomplish your task. Since they'll be pulling less than half of their normal loads, it oughta last a long time and get 'er done.
“Need help using my DTI 3300s timing meter on my 6.9 IDI.”