I've tried a number of things suggested here and elsewhere, but it's been nearly two months and nothing has worked so far. In addition to posting here, I put notices in the Flickr Lost and Found Camera and Photos group, IFoundYourCamera.net and CameraFound.com. If the owner looked on the internet, they couldn't miss it - a simple search turns up all of those. From watching the postings on these sites, there is a strange lack of "hits" from people who have lost a camera or a memory. It seems that it usually doesn't occur to people to try searching online.
I did review the pictures on the memory card and the EXIF data without finding anything useful. I also tried the image search as David suggested, but came up empty. An interesting variation I ran across had you upload an image from the camera so the search could scan for images with the same EXIF identification.
Certainly the suggestions offered here for making sure your camera can be traced back to you are good advice. In addition to the cost of the lost equipment, it's sad to think someone lost all those images. I hope they had backups.