I've hauled our '08 Honda GL 1800 Goldwing (right at 900 lbs) two ways. The first was on a Hydralift on the back of our coach and we just loved it that way. But, things changed and we now haul it on a Rampage lift, in the back of our 2nd toad, an '11 GMC Sierra 1500 Extended Cab 4x4.
I too have considered using a swivel wheel (or, there are TWO SWIVEL WHEEL models) trailer. I've been told by the manufacturer(s) (yes, there are several out there) that they ARE EXTENSIONS of the frame. But, like you are looking into, we've not looked into EACH AND EVERY STATE, to see just what their rules are. I'm the kind that needs to see things in writing before I make a large investment.
There are some 5vrs out there that are capable of a Hydralift and that kind of weight but, one would need to find all that out before purchasing the trailer. And, by the way, HYDRALIFT is not the only one that's capable of 1000 lbs. Cruiserlift, Blue Ox, and Overbuilt are all capable and listed as 1,000 lb. capable.
Interpreting each states laws when this kind of thing is investigated is sometimes quite a task. Since state law makers in most cases, are clueless when it comes to wording and specifics so that us regular, standard citizens can understand the meaning and, what does and what does not apply. Good luck on your search.
Scott