Guys, please excuse me for being so dumb, but what is wrong with sourcing a Level 2 K-case 700R4 from Bowtie Overdrives for $1650.00? This unit is rated to handle 450 HP and 450 FPT. It is the exact unit that I have bolted behind my P400 engine going into my M1028.
http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=B
Granted, Bowtie would need to add the Advance Adapters output shaft in order to mate up to your HMMWV transfer case, and this adds another $500 or so. And you would also need the TV bracket and HMMWV shifter, but you will need these regardless where the transmission comes from.
What am I missing in this thread?