There are at least three of us from California on the forum. The West Coaster is so well established, I am not sure how well a Northern California show would go over. That being said, I will attend if there is one.
BTW, I set up, in March, a group called the Southern California Toy Soldier Collectors Society. We have 15 members so far including some well know collectors (e.g., Ed Ruby, Bill Connolly, Neal Crowley, et al). New members are welcome. See my announcement in the Toy Soldier & Model Figure magazine under "Society Meetings" for details.