Nice looking setup there Boatycall
AirSafe coupler -
Class VIWe use the AirSafe Class VI unit with our WD head bolted to it. It works basically like the videos show on their website. When driving I can see the lower front of the trailer and a straight line at the bottom of the camper in the mirror at the same time. The trailer "floats" independent of the truck. I use it with a 7000lbs enclosed trailer for hauling bikes up to a 14,999lbs dump trailer. It really works nice with lighter weight trailers behind the 3500 series truck. Adjusted properly the coupler translates the fore and aft or "chucking" motion into down force absorbed by the coupler suspension.
With the camper loaded and the trailer coupled to the AirSafe and Torklift super truss the truck and camper actually ride better than no trailer mode.
I ordered it direct from AirSafe. They have different attachments - ball coupler, pintle, or WD that bolt on.
Minor cons: the unit with a WD head is heavy. And awkward - no flat spots to sit it on. I'm going to fix up a cheap hand truck to wheel it around on.
Your need an air supply to adjust the pressure for different loads, temperature and altitude. A good quality hand tire pump capable of 100psi is lots. By temp I mean -20F to 40F in the same day. We have on board air so I am wondering if a auto levelling valve wouldn't work.
Cost? the way the thing is built I figure about $10 a year :). It is sturdy.