I was going to suggest Howards as well. Love that place! Maybe check out a camping shop?? They might have something or be able to suggest somewhere else?
I got some storage bags from Kmart a few years ago, they are zippered, plastic on top so you can see whats inside, but the sides and bottom were a material (cotton?) which wouldn't be good if you got some wet stuff on the floor near them..We currently have some of DD's toys stored in them