Both CafePress and PrintMojo are in Northern California
(although cafepress doesn't do screen printing, they are in the Bay Area)
If you need someone closer to you, I would suggest trying the local phone book and asking a few of the screen printers listed there if they can do fulfillment for you.
We tend to stay away from printer recommendation posts because many of our members are printers and we don't want to encourage
self promotional posts.