I did a BOM with Fatquartershop.com and I was able to complete the original 12 blocks, do another 12 blocks and have enough fabric to do another 12 blocks. That's not including all the extra fabric I got in the finishing kit for borders and such. Two quilts easy with extra fabric for stash.
My local LQS is more modest in their BOM's with the fabric and I've had to go and get more when I mess up.