local upholstry shop - its the stuff used on outdoor furniture. they even stitched up the edges and sewed the sleeves for that price. u sound like u want to build one....
This it a great idea. I made some seats for my 16 a while back. They were uncomfortable to sit on and not that great to lean on. Never thought about something like this. Guess I have a winter project. (Pic of my old seats)
