Its been about 4 years ago but my local DMV let me title a WC52 that never had a tile issued. Once I convinced them that it was not a HUMVEE , I had to have them inspect the frame number, then I had to send a request to surrounding states to verify that vin# was not in use. Once I had proof from Idaho, Washington and California that Vin# was not being used. They issued me a title.
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Every state is going to be different, but have you tried a different DMV location?
It is possible that the people you are talking to just are
"stuck in their ways" and their
default answer is no.
What you are doing is no different than if you had built a vehicle from scratch and you needed a title. Is there possibly a
"License, Theft, and Weight Enforcement" section of your state highway patrol? Those are the folks
in my state that would come to your house or shop to
inspect the vehicle and help create titling papers.
Another buzz word you might try with the people who have already said no could be a
Bonded Title. The DMV inspectors inspect, verify serials, then ask for a chunk of personal information - and a small sack of cash to create a bond.