I recently bought a plastic pair from
The Loopy Ewe. They were inexpensive and that's what I was looking for right now.
You can also get some made of Sintra by
Fiber Trends or wood ones.
Leggy Creations sells hand embellished wood ones and
Chappy's Fiber Arts and Crafts sells wood ones with cut out designs on the top via Ebay. You can also find wood ones at The Loopy Ewe and Scout's Swag although they might be made by Chappy's also.
These are my results of an extensive search. I never did find a good pattern so that is why I ended up buying some. I figure it's probably $19 well spent.
You could buy one pair and then adjust sizes accordingly to make your own.