i just found them yesterday as well. i was looking for the vid of his door galley and stumbled onto them. the bumper vids were posted on dec 10th, so i assume they havent been available all that long.
i like the back bumper, but like carringb has mentioned, these setups dont allow back doors to fully open. i know it doesnt seem like a big deal, but with as much crap as i put on the back bumper, its really nice to be able to open those doors all the way to access crap in back when the bumper is loaded.
someday i hope to be able to build my own (or at the least hire buddies to construct, lol) bumpers and incorporate all the badass ideas everyone comes up with...along with a few ideas of my own