Guys it's not all about the trailer....the vehicle GVWR is the max that the Yukon can weigh fully loaded and the tow rating is the max that it can tow. The problem with tow ratings is that they are based on an empty Yukon with (1) 150-lb driver. As you add passengers and cargo weight, they subtract directly from the available tow rating.
By example, the GVWR of the 2013 Yukon XL is 7400 lbs, and the listed curb weight is 5820 lbs, leaving max carrying capacity at 1580 lbs. Lets you you, spouse, kids and luggage weigh in at 800 lbs. So 1580-800= 780 lbs available for the tongue weight of the trailer.
If we assume that a fully loaded trailer has an average tongue weight of 12%, then 780/.12=6500 lbs is what the loaded trailer should weigh without overloading the Yukon. Most families will pack an average of 1000 lbs of stuff in their RV, so 6500-1000=5500 lbs is the dry weight of the biggest trailer that you *should* tow.
Shopping by GVWR of the trailer can be overly conservative as most aren't loaded to the max. The dry weight on our TT was 6900 lbs, and the GVWR is 10,000, but packed and ready to camp it only weighs in at 8500 lbs. Yes, it can carry more, but I don't plan on bringing anything else with us.
The limiting factor on most 1500 series vehicles, both SUVs and trucks, is the carrying capacity, NOT the tow rating. Even with my 2500 Suburban, the 1200 lb tongue weight of the TT brings the loaded weight of the truck (with family inside LOL) to 8600 lbs, the GVWR of the truck.
Like everything else, use the above math as a guideline and adjust for your family and needs. The theme is this: You can haul a lot OR tow a lot, bot NOT both at the same time. The more you load in the SUV, the less that it can safely tow.