Thanks for all the replies. I find that my suburban is plenty stable when pulling the trailer, no complaints there. What I have issues with is the need for the suburban to downshift to second for every incline that we come up on. I am considering the 8.1L and the V-10 as well, but it seems there are a lot more 6.0L chevys around. Fuel mileage is not a big concern of mine, this will be a mostly dedicated tow rig, and the suburban gets about 9.5 towing now, so if I get less or more (within reason) I am not concerned.
I have thought about changing the gears on my suburban, 2WD so it wouldn't be expensive and I could do it myself. The concern is that it is my wife's daily driver and I don't want to sacrifice fuel mileage every day so that it does better the few times a year that I do tow.
Above all else, I have been without a truck for two years now and I "need" a truck.