National Geographic sells "Adventure Paper" specifically designed for inkjet printers.
http://www.ngmapstore.com/shopping/p...=75&itemID=351
"Print your own custom waterproof, tear-resistant maps! Designed specifically for inkjet printers, this paper will withstand the rigors of the outdoors. Adventure Paper produces a high-quality image and is easily foldable and temperature-resistant, so you can take it anywhere you want to explore."
It comes in 8.5"x11", 8.5"x14" and 11"x17".
I print all my maps on it, front and back. You can wad it up in your pocket, get it wet, etc, and it still looks good.
The paper has a kind of "waxy, plastic" feel to it.
rgds,
WT