I second Bonsaimonk.com as a great source for high quality imported pots. If for some reason they do not have what you are looking for listed online contact Karen at the email provided on the site. She orders from Japan twice a year so if you time it right you can have your pot(s) fairly quickly.
If you are interested in tokoname pots do yourself a favor and purchase a catalog. I believe the current catalog is the "Y" catalog from 2006. The catalog is stunning with over 100 pages but can be a bit overwhelming.
Here is a link to an online version of the catalog but it does take a bit of time to load pages. I believe somewhere on the site there is a list of pots no longer available.
Remember the dollar is very weak overseas and the pots are sold using the yen so you may experience some sticker shock!