Weddingbee boards

Depending on where you are located.  I went to downtown L.A.'s fabric district and bought the fabric myself.  They had quite a variety of dupioni and shantung silk. Having someone make the dresses for my BM's based off a picture with a minor detail change.  Not sure about time and measurements (all my girls had to go to the seamstress to get their measurements taken).  But it would only take her about 2 months to get the 4 dresses done (with all her other orders as well). 

try going to your local fabric store (a real one, not jo-ann's or someplace more craft oriented). Someone there should be able to point you in the right direction. Really high end fabric stores will even have their own seamstresses, but they tend to be a bossier bunch than people with their own storefront that are excited to get recommendations.