RE: What the heck is this stuff?
I may be wrong but I don't think it's a covering that you can buy off the shelf no way. I've seen the type your talking about though, I've got a Lion Models Cessna covered in the ame stuff. It looks great but your only hope if it's ever damaged beyond a decent repair is to strip it and replace it with a better covering such as Monokote or Ultracote.