NEVER, I mean NEVER, NEVER, NEVER get a tow vehicle based on dry weight. You MUST use the Gross weight. Dry weight doesn't include any pots, pans, blankets, bedding, etc. in its rating. The dry weight is also known as shipping weight. This is typically the weight of the rig when it comes out of the factory. It might not include the air conditioner and any other upgrades (like larger fridge, etc.) that add weight to the rig. Your hope is that whatever items and gear you put in the trailer DO NOT surpass the Gross weight of the trailer. The only way to know this is to weigh it, but knowing its gross weight is a great start!! You'll start approaching this as the tanks get full.
You might not drive with your rig with full tanks, but you will have to when they are full to get to a dump station or if you are on a long trip, you could run with some water in the fresh water tank for "bio" stops along the way and you want to use its toilet and lavatory. ALWAYS base a tow vehicle on a trailer's gross weight. Then you also have to remember the hitches and hardware add weight too.
I did a search for an official tow rating for the Suburbans you mention and there are quite a few options that can impact the rating, but it seems 9,000 lbs is around the number you seek. I saw numbers from 8,800 to 9,200 so there are dependencies. The sadness is there are plenty who give their testimonials of those who say "I tow mine with no problems". They won't know it's a problem until the right conditions cause something to break. Things break under normal operating conditions. Why would you unwillingly towing overweight and make matters worse. These are probably the same people that do not post AFTER a problem has occurred. I've witnessed that in other forums, that they'll ask how to fix a problem they had and you find out they were overweight and ignored it... DUH! You can be liable and negligent in the event of an accident, and you'll be paying for repairs due to this mistreatment of your equipment. Isn't it better to know you are safe, than guess so?
A big factor for towing power and efficiency is a gasoline engine versus a diesel engine. A diesel will tow the pants off a gas engine and get you much better mpgs in the process. The Ford Excursion is a good idea especially with a diesel and I recall its Tow capacity was closer to 10,000, but before you start running out and buying things, check your numbers!!! The Excursion might lose some tow capacity because it might be a heavier vehicle leaving less for cargo and towing.
Anyway, good luck on your search. The best to you, your family and friends and your recreational opportunities!