You might get the best advice from a belly dancing site that has instructions on making these bras.I know from beng in a belly dancing class that a lot of the girls made their own decorative bras for costumes from following these ideas. This link may help
Belly Dance CostumingJump to Bra Construction: Constructing a 'Cabaret-Style' Costume Bra - from Anthea's website. Variations & Techniques - part 2 of The Coin Bra - by ...
www.joyofbellydancing.com/costuming.htm - Cached - Similar