Something else I just was thinking about. Have you ruled out that it could be in the assembly? I know when I lost one, I actually looked through the high beam side and found it in there. The reason I looked through that hole was to borrow the high beam clip until I could find the other or get a replacement.

You might be able to get it with a magnetic telescoping pen or one of those flashlights that have one built in. It will take patience, but something to do on a snowy day