I actually have a mod for TS installed wich gives you the lght tower as well as other stuff.
and the GDI also uses it in the first mission of the campaign.
Yeah but they were kinda useless as buildable things. All they did was look around and do nothing. It would have been great IMO if, during night missions, your units would shoot slower/do less damage. But if a unit was spotted, all units would target that unit first, and get their normal ROF back.