This idea was brought to my attention today by someone who's thought about attempting it. Other than swapping in a Cummins, it would be a great way to have a reliable, 500 hp (tuned) tow rig that can also lug the family around. No more need for a "chase" vehicle, just load up the toy-hauler and hit the road with five friends. Starting with a Triton-powered version (for cheap) and dropping in a sourced 6.4L Power Stroke and 5R110 transmission could probably be done somewhat reasonably.