I decided to update this thread since there are two other Modulator II installations I noticed recently. Just on a whim while searching for a map of the system, before creating a new one to include all of the locations I know of, I happened to come across a map made by Coppell EM. Apparently there are more existing locations then I knew of and more proposed locations to come. It's very cool to see the siren coverage expand and it should certainly help fill any gaps that existed before.
New Tech High School: This siren location went in sometime before December of last year, but I haven't gone out to get pictures of it until now. This siren has a noticeable dent in the front cover of the battery cabinet.

- New Tech Mod II 1.jpg (55.13 KiB) Viewed 5074 times

- New Tech Mod II 2.jpg (44.38 KiB) Viewed 5074 times

- New Tech Mod II 3.jpg (60.9 KiB) Viewed 5074 times

- New Tech Mod II 4.jpg (39.91 KiB) Viewed 5074 times
Allen Road Park: This is the most recent location I was aware of (before finding the map). It is right off MacArthur Rd. This particular installation caught me by surprise since this is an area I pass by semi-frequently and back before June 2013 one of the last of the original style modulators was added Northeast of MacArthur and Sandy Lake Rd. This siren also has a dent in the battery cabinet door, but isn't as noticeable in the picture.

- Modulator II Allen Park Coppell, TX.jpg (41.84 KiB) Viewed 5074 times
Samuel and MacArthur: This location has been around for awhile, but since I passed it on the way to New Tech I decided to snag a blurry picture of it.

- Modulator 5020 Samuel and MacArthur.jpg (43.7 KiB) Viewed 5066 times