I have looked at the Uni-Go trailer also. My only issue with it was the fact it is designed to lean into a turn and drive the load down into the "standard" round motorcycle wheel/tire. With the Spyder it would seem to be side loading the connection joint and the wheel/tire. Since most of the weight travels low in the trailer it probably wouldn't be a major issue unless there was something of some weight loaded up high causing the top to twist the u-joint connector during turns/lane changes.
That being said, I have been looking at this
http://theusatrailerstore.com/rally-wagon.html trailer for many of the same reasons. I like the fact I can haul the bag in on overnight stays and there is nothing, but an empty flatbed to worry about behind my Spyder. It's not as stylish as the Uni-Go, but it is the way I am leaning right now. :thumbup: