I just got my new waterproof mattress cover in the mail. I put it on my crib mattress because the other one had gotten ripped on one half of it. Next week, I'm going to make a changing pad and use the old plastic on it. I'll take some plywood, put some foam on it, and cover it with the old pink nursery print plastic. It'll make diaper changes more fun.
I couldn't do it until I got the replacement mattress cover because even with snug plastic panties, I still get leaks from time time in the crib and waterproof mattress cover is absolutely essential for this sissy.
Here's a pic of the new cover: