Since there is no articulation at the receiver, in many states it is not considered a trailer...but in others it is. I do note however that Oregon does not require license/title. From their faq page:
Will I have to license and title the Swivelwheel system in my state?
You need to check with your state DMV / DOT licensing office. Some states do not require trailer licensing if under a specific weight rating. For example, the state of Oregon or Montana do not require licenses since the system is under 1500 pounds gross. The state of Arizona does not require licensing. Do not be fooled by competitive systems that claim that their single wheel or dual wheel system does not require a license. You must check with your state DMV office for information. If the Swivelwheel system must be licensed in some states, competitive systems must also.
My main reason for considering one is not to avoid tag/tax etc... but to give me the ability to bring scoots with us in a class A without having to deal with the backing, towing issues a normal trailer would have...as well as the extra length and turning considerations. The Versahaul hitch mount is my #1 preference if the coach can handle it.
The FAQ page answered a lot of my questions about the system:
Swivelwheel Frequently Asked Questions
I don't know that it is an appropriate solution for a 5th wheel... I guess that depends on the rig and the state. Anyway...I found it an interesting solution to MY problem.