Well, I'll say this, I have not see very much of ANY shortage in the amount of full size trucks and SUV's on the road. Although, I have seen a good amount of them for sale, including full-size chevy's, but mostly 90's models.
Suburbans are way too excessively sized unless you have a life-style that requires a vehicle of that size, honestly. They are longer, taller, and a little wider than the 4-door tahoe. Unless you have like 3+ kids, why would you need a vehicle that size.. with a V8!?
Stock Tahoes and Surburbans around here for 2003/2004 are going for about $5k
It's amazing how different the demand is for things from region to region. Over here in Massachusetts (well... New Hampshire was where I saw the vehicle) I was at the junkyard picking up stuff and I was looking at their repairables for sale. there was a 2005 Tahoe with a smashed rear window and a destroyed hood, grille, and front bumper. The junkyard was asking $8,000+
I would never consider getting rid of my truck and getting a suburban just so that my rear door windows can go all the way down. Especially where as I have already put work into this truck and am in the process of putting much more work into it. I'm with Yukalade. Why ARE you so negative towards modifying the rear windows to make them go down further?