Sure you can buy toggle clasps, but if you are a beader, why not bead weave a custom one to match your bracelet or even necklace design. Here are some of my favorites, starting with a basic brick and peyote stitch video tutorial the Beadaholique. They have great tutorials and instructors.
The Potomac Seed Company's video tutorial is different in that both sides of the clasp is accomplished with just peyote stitch. As you can see, there is scope for embellishment around the outside of the round part.