She picked the bodice, and the skirt is the same as the other dresses. This one is pretty close to several other lovely bridesmaid dresses out there:
I used (you guessed it!) one of my top dress patterns, Butterick B4915, for the bodice and midriff panel, and did a simple pleated skirt just like on Robin's.
There it is! A custom fit!
(If you made your bridesmaids' dresses, or did any other DIYs for your wedding, I'd love for you to share them in the Adventures in Dressmaking DIY Weddings Flickr group!!)