Hi guys. I just found out about this machine: Heidi Swapp's Minc Foil Applicator. Here's the official link: http://heidiswapp.com/minc/
You can also find many videos on YouTube showing how it works. The device adheres a layer of foil to paper. It's used for making shiny letters and drawings on cards, but maybe origamists can use it for costumizing paper for folding. You can probably easily make shiny duo color sheets that combine the folding properties of paper and foil. I don't have one so I haven't tested it. It would be awesome if someone from the list tried it out and shared the results. Cheers.