The past few nights I've been sewing with waxed canvas. It's thick and stiff and makes me grateful for heavy duty needles. I love the way the wax causes it to mark when scratched. Things were looking pretty smooth until I had to flip the bag right side out. Ooooh! The wrinkles! Instant character.
The wonderful thing about waxed canvas is that it's 100% natural and waterproof.
I've listed these bags in the shop.