Coquille & phoebe,
Hope you don't mind me jumping in here...
The absolute best source for tomatoes is the
Seed Savers Exchange which lists nearly 4,500 varieties. Over 3,000 of those are heirlooms. From your description, it sounds like you're looking for tomato varieties categorized in the "cherry tomato size" under which you should look for "grape tomato" types if you want them even smaller.
Another source I'd highly recommend is this
Growing Tomatoes Forum. Many experts in tomato varieties including
Dr. Carolyn J. Male and Craig LeHoullier frequent this forum and if you inquire nicely, you're likely to find some who will be happy to send you free seeds for a couple of stamps of rare heirloom varieties (which Alice Waters is certainly a supporter of) that have so much flavor you won't believe it until you taste them. Here's a
good thread for you.
Other excellent sources include:
Baker Creek Heirloom Seeds
http://www.rareseeds.com
Charles Wyatt (The late pioneer in heirloom tomatoes.)
http://www.heirloomtomatoes.net
Sandhill Preservation
http://www.SandhillPreservation.com/
Tomato Growers Supply Co
http://www.tomatogrowers.com
Cook's Garden
http://www.cooksgarden.co
Victory Seeds
http://www.victoryseeds.com