I picked up a small beef shoulder clod at a business Costco last weekend, and smoked overnight on Saturday. Clods are made up of a few muscles and typically include the chuck, tri-tip, and flat iron areas. Most are 25 lbs or more, but I found one a little over 13 lbs. I had a few technical difficulties, but it turned out great, even more flavorful than a brisket. Pics can be found here.