I looked around all sorts of places yet I couldn't find anything the right size but at the end of my wits a shop owner who sold kimonos fixed one up for me to be used by kids. Kimonos are made up of these long and thin fabrics split into parts called "tan" and isn't it amazing that they put these rolled up fabric parts together to make something like this? There's a particular trick to sewing them but sewing them by hand seems quite troublesome. There's also this "obi" or whatever and you wear a lot of them like layers...