Thanks to all of you for your good suggestions! I called the national customer service number and talked to the nicest guy. He was able to tell me that the car WAS previously rented from my location, which means the local Avis person I talked with was either misinformed or apathetic or both.

I called back to the local office this morning, and got someone who could obviously use another cup of coffee before she answers any more phone calls. She said that lost and found claims go through their regional lost and found department, but she repeatedly refused to give me their phone number. She said to just bring the camera in when we return the car (my son's car is in the shop for repairs, could be a while longer), and Avis will "take it from there". I've read several dozen Avis horror stories of things not making it back to its rightful owner. It's not that I don't trust them, but I trust ME more. I feel confident that if I was going to steal it for myself, I would have done so by now. Every time I tried to explain to this woman that I wanted to return the camera directly, I got the "You have to turn it in to me!" speech, only louder. I really don't want to do that and just hope for the best.

All the video was taken in Chicago, so I've been keeping an eye on Chicago's Craigslist lost and found; I guess I'll start looking a little closer to home. It's hard to believe that no one reported it missing - we've had the car (and the camcorder) for a week and a half. I probably burned my bridges with the local company; when the Avis employee started literally yelling at me over the phone, I said "Never mind!" and hung up on her. But I might try the national number again, and definitely Craigslist. Thanks so much for your help!