http://www.amazonexotichardwoods.com/Merchant2/merchant.mvc?Screen=CTGY&Cate
gory_Code=TB-AFB

You can also find some different types of hardwood on this site, but for
using theese blanks you would need to have a lathe, that would be the
easiest way for you to make your mouthpieces.
Good luck!

Best Helge