There is always Tandy's moc patterns - they start at Women's size 4. I would think you could reduce on a copier if needed.
https://www.leathercraftlibrary.com/p-1172-moccasin-pattern-pak.aspx
There are a lot of stamping patterns for belts here that I think will scale down to a wrist band. Try a search on belt patterns - here is a recent one: http://leatherworker.net/forum/index.php?showtopic=46725&hl=