I found the cutest tutorial on Noodle Head for a diaper pouch. It can hold some travel wipes, a few diapers, and some diaper cream.
The tutorial was really easy to follow and the whole thing took less than an hour. I put a Target Up & Up diaper in there and one of my son's Sunbaby cloth diapers, just to see how it fits. I think it's large enough to fit two Sunbaby diapers and a case of wipes. It's perfect for the baby shower I'm going to next weekend.