I feel like I have some closure and potentially some answers for some others. I was able to order a new LTZ Tahoe today which was fine, I added the retractable running boards, and the upgraded 22'' wheels. I previously had the "standard" 22'' wheels but wanted something a bit different so I'm happy, but have to wait 6-8 weeks for it to get here. I wanted to order the Denali but because this is a transfer of equity with the bank I had to have the same make / model. I'm fine with it really.
The other upside is they are letting me drive my original truck in the meantime. They've said the service 4WD light isn't a safety issue so I thought it good of them to go this route.
The service rep told me it's better to order one as the issue with the transfer case is in a number of unsold trucks and they aren't sure which ones are affected. So, if I were to have taken one off the lot I may have been in the same boat in a few hundred miles. He went on to say the issue is with using the truck in auto as opposed to 2WD. For some reason in auto is causes some transfer cases to heat up and throw the light - but using the same truck in 2WD doesn't cause the problem. Has to do with the clutches being too tight. So...for those that haven't used the auto setting, you might want to for several hundred miles just to see if you got a bad transfer case or not.