Just got back from the DMV and after lots of back and forth and arguing they were finally willing to register us as a Motorhome and not as a commercial vehicle. The big point of contention was the fact that we don't have seats in the back, which according to DMV automatically makes us a commercial vehicle and we would have had to pay weight fees. After explaining to them what we are planning on doing building it out as a camper van the DMV lady softened a bit and said "I'll have to ask my boss"...by the time we went back inside after looking at the NV her stance had softened further and she shredded the form she had filled out and started anew mumbling quietly "It'll be a motorhome then." And that was that. Got lucky there. Not sure how much difference in terms of registration fee (and vehicular sales tax since we didn't pay that back in VA) would have made, but I am glad it all worked out. So, anyone else registering in CA, just throw a fake bench with seats in the back or hope for a nice DMV person...;-)