I have no experience towing with a Sequoia but I know a fellow who tows a 30 foot Starcraft with with an eariler model Sequoia. Check out his web site at http://www.paushe.com/toyotasequoia.
The Sequoia's 4.7L engine may not sound impressive at first glance, but it's OHC and VVT engine coupled with its 5-speed tranny delivers all the HP and torque of my 5.3L push-rod Yukon, which I've used to tow a 30 foot ultralight myself before trading to our new-to-us 25 foot Safari (which should be a walk-in-the-park in comparison as it's only 200 lbs heavier, 6 feet shorter and much more aerodynamic).
With these SUV's the two things you have to watch out for is not exceeding the GVWR as their cargo carrying capacity (CCC) can be limited and you have to pay attention to the anti-sway hitch system due to the short wheelbase. A Hensley isn't necessarily essential, but it's sure nice to have.
Power wise these SUV's can do nicely - within reason and depending on your expectations (read, it ain't no diesel).
BTW, in comparison, he gets about 10%-20% better mileage (towing and not) than I did because of the Sequoia's smaller displacement engine, but now that I've traded to an Airstream, that should even things up.