I looked into this issue in California as I considered purchasing a stovebolt without a VIN. I did get the "Don't buy the car" speech from DMV.

I could be wrong but I understand that in California, DMV will send you to the Highway Patrol for a VIN check and if the car does not have a VIN, the Highway Patrol will issue you a "blue plate" with a new VIN. You need to bring your bill of sale and all other information. I did not purchase the truck so I am not certain if this is accurate. The DMV Help Line staff were not aware of this "blue plate." There may be some hope.