Try
www.fabsearch.net - I got it from the FabShop website. I needed about a yard of a fabric for the border of a round robin quilt, and tried this site. They send out 1000 emails to quilt shops all over the country letting them know the fabric you're looking for, and the shop(s) that have it will email you with the amount of that fabric they have and the price. I was thrilled with the result - I got the fabric I needed (only 1 store had it!), and it was even on sale!