I have just seeded some unusual plants from Yuko's Open-Pollinated Seeds: manchurian plum and nanking cherry. She also has lots of other interesting varieties that she saves from her garden and sells at reasonable prices including Mitsuba (perennial japanese 'parsley') and a variety of ground cherry that amicably sows itself around her garden. This company especially interests me because it is local so I know the plants are adapted for this climate (if not my particular garden conditions).
I also visited (and promptly bought seeds) from Solana Seeds who have recently translated their webpage into English. Stunned by the number of plants including Piel de Sapo melon (a keeper melon), Red okra and more solanum berries than you can shake a stick at, I decided to try more french websites and bumped into La Societe des Plantes who made me swoon by selling turnip rooted chevril (I was beginning to think this veggie was a myth) and skirret (perennial 'carrot' relative) seeds. Both these Quebec companies also sold scozonera (another potentially perennial veggie I'm trialing here) which I could not easily find in NA prompting a kind European blogger to send me some seed from over there (I'm not linking him only because I don't want people to think of him as a courier ;-).
One final company that I quite like is Wild Garden Seeds as they genetically mixed seed packs so you can do your own selection for a variety suited to your microclimate.
Thought I'd bring these smaller seed company to the attention of locals and perhaps even those further abroad.