I found this thread and a couple of people said they made their own, not sure if they sell them or not though...
http://www.yorkietalk.com/forums/sho...ht=belly+bands
Also choloeandj, one of the ones who said she made some does sell clothes so I'm sure if you asked she would make some to sell to. Can't hurt asking, I guess. If this doesn't help maybe someone else will know more, I have a female so I don't really have much experience with them.