I have been considering getting one to make a dog bed for DD boyfriend's new dog, using his no longer needed XLT egg crate mattress pad as padding. Thought it would make a cheap, comfy bed for his new baby, who is already 50+ lbs. at 6 months old. I would want to put a zipper in it so it could be washed. That'll be expensive part. Hope I don't have too much trouble finding a really long zipper. I've never looked for one before. Any suggestions?