Once the RTT comes in I am going to be working on a retractable roof rack for the tent. It will fold down for transport and fold up when deployed. Since the RTT has an annex below it, I want 6 feet from the bottom of the tent to the ground for head clearance. I still havent quite fully wrapped my head around how I'm going to do it. It should be an interesting project though.
I was thinking about this same sort of thing for my own trailer, I just don't have any plans to mount an RTT to it any time soon, but want to make provisions for it if I choose that option later on.
I was thinking of having some vertical tubes mounted on the exterior of the trailer with an open top and bottom end and drilling pin holes through the sides about 3/8" diameter. (Use bolts or quick release type pins like in a receiver to secure the rack in a certain position.)
I was thinking about putting 6 in place, 1 in each of the four corners and 1 on either side of the trailer in the middle near the wheel wells.
Then all you have to do is use a matching size of tube that could slide into the "holsters" you've just made, and make an appropriate rack to hold the RTT.
This isn't a very fancy or elegant method, but it would be very strong, and versatile because you could mount other items with these vertical tubes when you don't have the RTT mounted.
Having said all of that, I'm not sure how you'd raise the apparatus in a manner that would keep it all level and prevent any binding...
If you've got a couple hundred pounds on te rack and trying to raise and lower it, you're probably going to need something to assist in the effort.