I know this is crazy old, but people like me come here looking for things like this, so I wanted to provide an update. I went to a few of the current auto-parts stores and they looked at me like I was insane. They had similar connectors, but none with little handles. You might be able to get one with a plastic screw, but I'm one for the "correct" equipment.
Through DAYS of searching I found that currently (2021) Leviton Structured Media uses these exact clips, in black, to mount things. I was able to get a pack of 20 off of Amazon for a shade over $5 (2021).