Yes the hummer H3 5 speed will work..(belhousing change). as will the factory H3 low 4.3:1 transfer case that is in the H3!!!!!.....Ive done much exstensive research on this and will be doing this exact swap soon...
the TOD computer is SEPERATE from the computer that runs the auto tranny!!!!! And it ONLY operates the TOD.
Also the H3 transfercase is built just like the VXs and is in fact also of "TOD" design meaning elrectromagnetic clutches that engage 4x4....
Lastly, You CAN mate up a ar-5 out of a 1999 trooper to a stock VXs transfer case. AND keep TOD..they bolt right up!
another possibility is the 6-speed out of the FJ cruiser (belhousing change to ar-5) mated to the H3 transfer case!
This has been spoken on before a while back....
Go for it.....