I vote keep looking for the Yukon XL or Suburban.
When I was shopping for a new truck, I really wanted the longer wheelbase for the extra 2 feet of interior space. But I got my yukon for a good $$ due to the bad motor. I settled. I compromised by buying a rack and building a plywood box to fit inside of it, and a couple of roof bags.
For trips or otherwise I've used the rack a few times. Each time, I wish I hadn't settled for the short wheelbase.
The moral of my story? If your not in a hurry, wait and get what you want. If your buddy has a car lot, then ask to goto the auction with him. Offer him $100 over auction price on what you buy.
EDIT: Don't be lured into compromising your wish list by the eye candy of the Escalade.