Try these guys. They have good pricing and selection. I've used Blue Nile for diamonds, these guys are equal in the pearl game.
Exquisite Pearls & Pearl Jewelry at Great Prices - The Pearl Source
You can check out Glendale Jewelry Mart or L.A. Mart, you might find some deals there. If you want vintage, I can check with some propmaster friends and find some reputable dealers also.