Have you tried Hurley bathing suits? I have one and love it! They have sewn in (light) pads and they are sporty, which makes small chested women look hot!
BTW, I am 5'3 and 117lbs and a 32A at Victoria Secret. I have struggled with my chest size for years. I actually got sized for implants and couldn't go through with it. I'm about to graduate law school and have always been a bit worried about being so small on top and how that looks when I wear my suits, etc. My soon-to be fiance loves my body and to be honest that is all that really matters anymore.
Anyways, I have finally come to terms with my chest and I like to think that my body is proportionate. It used to bother me so much when I was younger because I was so small, but as you get older you realize from other women that you are very lucky to be the size that you are. I teach aerobics and cannot immagine how painful bigger boobs would be during my workout!
So cheer up, because you are not the only one with a small chest