This topic is still on my mind. I have a Kelty Trail Ridge 2 set up on a Roll-a-Cot Wide in the house right now. The tent feels very spacious on top of the cot. Lots of headroom. The only problem is that the 4 corners of the tent are sagging because the tent is larger than the cot by 10-12" all around. I have an idea for a very simple solution: legs for the tent at each corner. No platform needed.
Cut 4 pieces of PVC pipe the same height as the cot. Put the tent on the cot. Place a pipe at each corner of the tent. You could drill a hole in the pipe and run a cord through it to attach the tent, although I think that the staked fly will provide enough stability.
Limitation: You wouldn't be able to put anything heavy on the floor of the tent because it wouldn't be supported around the sides of the cot. Solution: A plastic gear box under the cot plus a gear loft in the tent.
What do you think of PVC legs for the tent? Simple, no?
cause they are nice cots