I have quite a bit of experience towing with two Armada's. We had a 2006 and a 2008. The 2008 towed a 30 foot Starwood and a 30 foot WindJammer. It did wonderfully with the Starwood, and was too short of a wheelbase for the Windjammer 3065W. I pushed to GCVWR of 15,500 on more than one occasion, and was very pleased with all aspects of the towing with the Starwood. When we moved to the WindJammer, the weight was about the same, but the length was different. I felt like the Armada was too short. When I moved to a Tundra, I felt like I had the right length.
That said, I would stick to a trailer that's between 28 and 30 feet in real length. The Armada is a GREAT tow vehicle, especially with the on board leveling and a good weight distribution hitch like an Equalizer. Keep in mind that it's shorter than a pick up, and that it can wag. If you pick the right trailer then you're in. I towed with it for roughly 20K miles. Don't hesitate to contact me with any other questions.
Ct..