Your best bet is to head north and fish for them in OR or WA. Hatcheries have a minimum for shipping and the shipping won't be cheap. You'll also have a problem finding a hatchery that'll ship walleyes to CA since they're on the Restricted Fish Species list.
Jonah's aquarium does special order them but they are seasonal, the good thing is you can buy just one if you want. The other sites I have seen have 500 lb minimums. that is around 5000 small walleyes , got a real big tank?