I was told the MT8 (88-94) NV4500's have a different bell-housing to transmission bolt pattern than the dodges. The MW3 (95+) NV4500's are the the same as the dodges, so with a newer one it would work. It would take quite a bit of adapting to get the Chevy tranny bolted to a cummins, along with the input shaft swap that 454 mentioned. 454 is also correct about the accessory problems, but there are fixes for that.
HERE IS A GOOD CUMMINS SWAP:
Crummins did a great job on this in his Burb, but he used an automatic so it was easier to mate the engine up to the tranny.
http://www.gmt400.com/forum/showthread.php?15670-1996-Suburban-Cummins-Swap!
Anyways, update. My rear view mirror decided to fall off of my windshield, and pull the inner layer of glass off with it, so I get to spend my money on a new windshield instead of the tranny. Oh well, guess I'll keep an eye out for one later. I'm starting to believe the best way to do a Cummins swap would be to run a Dodge tranny and drivers drop Dodge transfer along with it, but then I'd probably have trouble getting the speed sensor to work. On the other hand, I've actually been looking into LS swaps more now. I am surprised there haven't been any LS supporters here haha. Anyways, guess I will just sit back and keep researching for a while. Still open to suggestions though.