Thanks very much for your suggestions; they're all good, and I will be following up with each of them.
A few updates since I posted last night...
1) With regards to the Craigslist posting, it seems everyone has either lost a camera in that area or is hoping to "win" their dream camera if they guess the right make and model. So far, no one has it remotely right, and in the ad I asked the owner to identify not only the type and brand of camera, but the kind of pictures taken with it. I recognize the people in the pictures as some of the ones who lost it, but nothing beyond that. Makes identifying the rightful owner(s) easy!
2) You've collectively jogged me into thinking of an untapped possibility -- the uni newspaper. I can place an ad there, and it might hit the target audience right away; thanks!
3) Unfortunately, the camera is not in production, so the manufacturer cannot help me there (tried).
4) I went through the EXIF data straightaway and found lots about exposure information and such, but sadly, nothing to help me return it.
5) I'll post an ad on the bulletin board of the uni bookstore, referring to the Craigslist ad. That will help, I'm sure. Current enrollment is ~20,000, so the bulletin board should help me find the party more quickly (the group looked a bit old for high school, but about right for first- or second-year at uni, judging by my past students; these were a nice group of young adults, polite and friendly).
I'll post an update as things develop. Thanks again for your suggestions, and I welcome any more that occur to you.
Best,
Dan.