If you are in San Jose, just drive up to Hayward and see Johnny Uchida at Grove Way Nursery. he has plenty in 4 inch pots. I recently picked up some japanese maples seedlings to make a small forest planting. Most were double or even triple planted so I got nine tress of varying sizes in only three 4 inch pots. At $8 each, I did the entire planting for only $24 plus tax.
On the plus side you actually get to see the trees and some amazing bonsai as well! He is only open Thurs.- Sat though. So you just missed him this week.