Any chance you have a record of the VIN...old insurance cards, registrations, etc.? You may be able to do a title search and find the current owner, if it is still registered and licensed.
The owner of Papa Johns Pizza found his '72 Camaro, after several years...but he offered a $25K reward, to do so and bought it from the current owner for $250K! Here is the link to the story:
http://www.mahalo.com/papa-johns-camaro