I answered my own question--but I thought this might help someone else.
www.exelnt.com
They have a large swimsuit store in Michigan and they manufacture their own swimwear for nearly all sizes and shapes of women. You can select your fabric, choose a style of top, bottom or one-piece and they will make what you want in your size, if they don't already have it in the store. (Check our the online catalog.) The suits are quite expensive, but I think they're worth it if I get a suit that fits well. And if it doesn't fit, it can be returned.