In CA, when you register a vehicle (new or used) for the first time you effectively pay the state sales tax rate. In my county that was 7.75%, so registering a bus can be a pricey proposition.
I guess it's fairly common (with cars at least) that people try to avoid paying the road taxes by registering out of state. I've been told that they now have people watching out of state plates on the highways, and when they see the same plate for more than 30 days, they can go after you.
I've never seen it happen, or actually hear about anyone getting caught, but I've heard the warnings.
I think it might be cheaper to move!! CA is getting way to expensive, and I wanna get one of those large garages and dig a pit too!!
Ray