I am very careful with breeders who are willing to ship their puppies since it puts them under alot of stress and I won't know how well they have been socialized. They could also come from puppy mills.
You may want to try going to a few shows and meeting some of the breeders in person. Jack Bradshaw is the show superintendent for the so-cal area. To see what shows are scheduled just go to thier website and click "shows"; from there you can get directions to the shows and see the judging program to find out when and how many Shibas are in the show. There's a 4 day show at the LA fairplex in pomona this weekend. Looks like there's 14 dogs entered on Sat and 11 on Sun, which is quite a good turn out for Shibas. There's also shows in Pasedena and Chula Vista comming up.