What online site can I find a wedding dress that is non-strapless, lightweight, no sequins, and no v-necks?

This wedding dress is for my sister and needless to say she is very picky. We've tried David's bridal and she's looking for something unique. I've also looked at vintage stores and my last resort is going to be designing her one with the bits and pieces of dresses she does like. She wants the dress to accentuate her upper half and maybe have a cool sheer back. Help:)