Jeff, what you need to find is whole, untrimmed brisket ("packer cut", both the point and the flat sections). The grocery stores around here carry the flat sections only, and charge $2-$3 a pound for them. So, I can get a 10 lb. whole brisket at Wal-Mart for about the same price as a 4 lb. flat at the grocery store. Go figger...
Good luck.
Steve