I like the idea and could have used it this past winter. I ended up making my own platform between the rails out of some spotted owl trees. I don't like those tall, top heavy looking racks. Their nice but impractical for my needs.

I think the "bouncy" ideas are a bit overstated since you have to strap everything down anyway. If you did it right the first time you wouldn't have any movement in any direction. If you have any movement your not tight enough on the straps and you may need to repack so you can get it tighter. That goes with any kind of rach system. I always use ratcheting load straps so that I can be positive of my loads secured.

I'll take one of these if they make some of the changes that have been mentioned here to make it a little bit stronger. Besides it would come in handy for the 4th of July fireworks and our local Air Shows as an elevated hamock!