I have a troupe mate with the same costuming problem. She bought a couple of beaded shawls like these (link below), sewed one to a comfortable bra, and made a belt with the other two by sewing them to a pre-made belt form. I think you have to put a drop of nail polish on the ends of the fringe on these shawls to make them sturdy enough for dancing, but that's easy enough.
http://cgi.ebay.com/HANDMADE-BEADED-...QQcmdZViewItem