From my experience with my uncle the vehicle will have to be used in order to get in licensed in CA. My uncle bought a TDI Jetta here in AZ with the thought of driving it back to Santa Barbara. They would not register it for him in CA. He transferred it to my name and I registered it in AZ and then sold it back to him. He took it to CA as a used vehicle and they let him register it. I'm not sure if this still holds true or not. I would bet that someone on the Hotboat.com forum in the Sandbar will be able to answer this question for you. There are lots of people who go back and forth from CA to AZ around the Parker and Havasu areas that hang out on that forum, good luck!
BTW, has anyone towed with one of those yet, or are they still brand new?