Build Jeep from new frame/body...what about VIN # for DMV?

So I had this thought of building a Jeep from scratch. Like using a new frame, new body, and adding motor, tranny etc as I go along. Then I wondered where does the VIN come from? There are no donor vehicles in my scenario and even if there were, their VIN's are for their carcass, not my Frankenstein rig. How is that handled in average DMV's?

I am in California, but any ideas or knowledge on this would be appreciated.