Joe,
As you have a family trust, you might investigate the trust putting a lien on the car. That way if the prior owner does show up, they can have the car, but need to satisfy the lien. So in a round-about-way, you would wind up getting your purchase back.
The ability to do this varies from state to state (and I am certainly NOT an expert in this) but we have successfully done this in Oregon with a car that was lost title, last titled in California.
Just an idea from someone who did not sleep in a Motel 6 last night nor has she finished her morning cup of coffee.
anglea