I saw the Jay Leno demonstration as well and was very impressed with it. IIRC it's on Youtube ? Anyway, I seem to recall someone on Lotuselan.net was having a go with a similar sort of material on some +2 front sidelights last year but I haven't seen any progress reports just yet.
It impressed me that it could be a perfect solution for those cast parts such as lamp bodies & small fittings which tend to pit badly and are difficult to repair and re-chrome successfully. If you could just fill the holes, smooth down and paint over, that would make a lot of scrap parts re-usable. Maybe not so much for bumpers which get knocked and damage a lacquer topcoat, but lamp bodies, especially those recessed such as our cars, would be a good option.
