Dave have you run the vin number at the US Government title clearing house database? She may have been sent south to the States after 81 and has been on record since then. The database will list every title hit - registration, or scrap the vin received here in the US. only 5 bucks USD so worth a shot. http://www.vehiclehistory.gov/
All the vendors attached to the program have access to the same data so the only difference is the output of the report. Some are glossy with loads of goofy graphics, and others bare bones with just the data. I use Auto Data Direct because the reports are easy to read and they take paypal payments. http://www.add123.com/
Good luck and I hope you report that you have found her.