For those looking to purchase swimsuits with support, I found these:
http://www.cyberswim.com/
http://www.swimsuitsforall.com/prods...dept_id=101288
http://www.alwaysforme.com/bustsupport.html
http://www.athleta.com/products/dd-swimwear.jsp
I just think it would be *so* much easier to purchase a suit with an underwire bra than to try to make one. There are so many pitfalls in making a swimsuit!