So I just happened upon this video tonight:
https://www.youtube.com/watch?v=FwYmouFZpuM
Not sure if this has been posted before or not, but I have yet to see it on the board here. Thanks to PeachtreeSirens, we have confirmed that this system was in Dade County Florida. I'd be interested to see if anyone else knows anything about this system. According to the video, this siren was mounted atop the Dade County Civil Defense office, which I am unable to find despite the cross streets being mentioned.