I've watched your adventures in transmission destruction for years, and have always wondered why you didn't move up to a Medium Duty with an Allison. I wouldn't buy a 2010 or later diesel on a bet, but last I knew (and it has been a few years) you could buy a new Low-Pro Navistar or Freightliner as a glider and have the dealer install a reman driveline. A 5.9 or 8.3 mechanical Cummins or DT 466 with an Allison behind it should be pretty bulletproof for 500-750k miles, and with a Texas-hauler bed and 19.5 rubber, you wouldn't be much different than an F550...