Where in So Cal? If you are in the L.A. or Long Beach area, Blacksmith's Corner on Lakewood Blvd has bantam chicks, though maybe not this time of year. They won't be sexed, though.
I got my bantam cochins from a show breeder as started pullets, they were the "rejects" that were not perfect enough to breed for show, but they were far better quality than most I've seen from hatcheries. That was many years ago, since the last two girls died last year at the age of 10. I went to a poultry show, I think at the Costa Mesa Fairgrounds, and found exhibitors there who had pullets for sale. Some had hatching eggs for sale, and I think I might go that route this time around.
You can also try Craig's List. I am always surprised at how many chickens are listed there. You'll just have to know how to spot a cockerel, because I've seen some shady ads for "hens" that obviously weren't hens. And you don't know that they aren't sick, either.