Do you know if she was microchipped? If she was, you could tell the owner to call ALL the Vets' offices that she possibly can, get their fax # and send the info along with a picture. Same thing with all the shelters. Tell her to call all the local TV stations to see if they won't help and run a picture.
This is getting worse and worse. It's gotten to the point where I won't even take my girls out anywhere unless my husband is with me. (except for play-date) I use to take them to the parks, rides in the bike basket, walks, and to different stores, by myself, but not anymore. Maybe I should have just gotten a mixed breed dog.