Has anyone used one of these? Not cheap, but nothing in our hobby is. Sounds like a good concept.

http://airsafehitch.com/air-hitches/receivers/class-vi

Lots of good ideas out there for towing. Most are gimmicks. This sound like one. It puts your trailer ball farther from the rear axle. More stress on the receiver. If you use a weight distributing set-up and get it adjusted correctly, you don't even know that the trailer is there. My Excursion rides better when my 28' enclosed trailer is hooked to it. The boat is no different. Get it set-up correctly on the trailer and it will feel great. I played with my Scarab III on a tri-axle for 2 years to get it right. Now it's straight as an arrow at up to 80 MPH. Same with car trailer. If your really concerned with tongue weight and not getting the "shock" to your butt, get a Trailer Toad. They are awesome. I know 2 guys that have them and I'm jealous of them.