Ideally, you want the material to be tough enough to be bite-proof, a bit fuzzy, perhaps, but not so hard as to be a tooth breaker. Cat-proof Christmas tree ornaments are another no-brainer. I'm also waiting for my d9. Just make a dreidel shape with an arbitrary number of sides. I'd suggest d3, d5, d7, d9, d11, and d13, just for lulz.