Gerardo recently asked about the plastic/aluminum laminate used in coffee bags. I have been folding models from old coffee bean bags for many years. It is fun to fold and remarkably (nay, depressingly) durable. I use it for wallets, mostly. Not only long-wearing, but also infosec-chic: the aluminum keeps RFID-sniffers out of your backpocket.
Bigger bags can be had at cafés by asking. Yours, Philip Chapman-Bell Northampton, Massachusetts