Originally posted by mikey
And do Airstreams' superior aerodynamics and stability enter into the equation?
Physics laws are physics laws. That said, a rule of thumb is rough guide. The more learned members of this forum can do the math to illustrate the point but generally speaking, the bane of trailer towing is the tail wagging the dog. The shorter and lighter the tail, and the heavier and longer the dog is, the less likely the dog is going to be wagged by the tail.
I tow a 34' trailer with an Excursion. By the "rule of thumb", I ought to have a one-ton crew-cab long-bed as a minimum. I will tell you though, that with a proper hitch setup, my Excursion handles the weight and the length very nicely. It is the heaviest and longest station-wagon type vehicle available right now, and I didn't want a truck. It is about a thousand pounds heavier than the 3/4 ton Suburban; however I looked at a number of Suburbans as well and would have bought a Suburban had I not found this particular Excursion.
Make sure your tow vehicle is adequate for the weight of the trailer, both GVWR and CVWR, as long and heavy as you can get in it's class, with an adequate hitch properly set-up (I have a Reese dual-cam; folks who have Pull-rite and Hensley Arrows swear by them), and tires that will handle the additional weight, and you should do fine. Just don't push the envelope too far.
There are numerous threads on towing, hitches and the like on the forums and I encourage you to read through them all. You'll have quite an education when you're finished.