I don't know of a specific place offhand, but any bakery should be happy to make a pate brisee or sweet pate brisee in whatever quantity of tartelettes you like. Heck, it's just pie crust. The only hard part is owning enough little tins: A thing at which commercial bakeries excel. Start with your favorite bakeries. It's also worth cruising Little Saigon, there are a pantload of excellent French bakeries down there. Unfortunately, OC isn't my beat and I can't be more specific.
If you're dead set on buying them pre-made, the best advice I can give you is to ignore the inevitable advice to do it yourself with the promise that it's easy. It is easy, but not as easy as someone else doing it. The second best advice is order a lot of extra -- they're fragile outside of the tin.
FWIW, the alternatives to pate brisee are pate sablee (short bread) and pate feuilletee (puff pastry). A good French bakery can handle any of these.
If all else fails, buy pre-made puff pastry from the market, and some tins. They run around $10/3 doz. Spray some baker's non-stick in the shells; then lay out the puff pastry, and use the tins to cut the pastry -- the walls slant out, so the pastry will go partway up the sides when you lay it in. Use your thumbs to work the pastry up to the top of the mold, pressing the dough into the little crevices; bake the shells off until just brown, let them cool for five minutes (they're small, it won't take long), turn them out; and start the whole process over again. Using pre-made pastry, you can easily make 150 shells in 2 hours. They freeze well, so you can do it a week or so in advance if you like.