Very neat. A waterproof bag might be a good idea there! I do find I need a rubber mallet to get the seats back into place...
I use a zip loc baggie to hold registration papers under my standard seat. Never had to show it yet.
I am with you on that one Stephen, I raised the seats with wooden blocks and use ziploc bags to hold the various items I carry, best thing is you can see whats in the bags.