Dear Don:
In 1999, I built a Ryan RSK-718 which uses body molds supplied by GP Technical on a 1969 VW pan. I wanted to use a std. VW pan so I could register the car easily and pay annual tax on a 1969 VW bug, about $35/year. Also, much easier for the individual builder to do a VW pan model than a tube frame. According to the DMV here, all I had to do was to be sure I had the original manufacturer's VIN code that is stamped onto the top of the shift rod tube (hump in center of pan that runs front to back) just in front of where the access port is for getting at the Transaxle/shift rod coupling. Different states/countries have different requirements.
Since I kept the original chassis (shortened 11 9/16")it was decided that I had kept the original car, albeit with some "body modifications". It all seemed too easy, but after 8 years nobody has bothered me and I drive regularly. I did have to take 18 photos of the car for the Automobile Club (AAA) which was the only source I could find to insure this car for actual value (at the time, $20K, certified by Ryan Motors, long defunct now). I don't have any photographs of the chassis prior to mounting the body, however.
Ralph Glorioso