I would think the conversion would be very complicated with all the electronics involved. But maybe it's all plug and play and not as bad as I think???
If you're going to go to all the trouble to install the Duramax engine, I would for sure install the Allison transmission. You don't want to have a weak link in your powertrain.
Anyways, I hope that you end up doing the conversion. It would be a unique vehicle. However, if it's too complicated, you could always do the Cummins Tahoe conversion like what I've got.
1990 ¾ ton 4x4 Chevy Suburban
-Cummins Diesel - 12 valve - factory rebuilt
-6 speed bullet proof manual transmission - NV5600
-Gear Vendors Overdrive
-Upgraded Holset HX-35 turbo
-NP205 iron transfer case
-3.73 gears
1982 ½ ton Chevy Suburban
-6.2L diesel - high nickle crack free 1982 block
-Stans headers
-Ported heads
-Timing gear
-4 speed automatic
-3.08 gears
-30 mpg on freeway