Donna, two places I have seen bases are in my Little Shavers and MDI catalogs. MDI has the biggest selection, finished and unfinished and different shapes. I don't know if they have any shown on their website, the address is
www.mdiwoodcarvers.com if you want to check it out or order their catalog if you don't get it.
Rick at Little Shavers, address
rick@littleshavers.com would be a good person to check with too. I only see a couple round and oval bases in their catalog but he's good at helping you find what you're looking for. Let us know how you make out, I for one will be most interested, a few of the carvings I have drawn up for this year will require bases and not making my own would be a real time saver. Good luck! Callynne