Heh, I was thinking of trying something very similar (fixed turret with arms of Stud Lazers). I don't think that wide base will anchor (well) anywhere in a campaign world, though. Unless the anchored enemy deployment is like the load techs option in Creative, so will clip it into the terrain...a massive multitech turret which I named "come at me i daer u"
Does the turret actually point at you reliably, when it's set as an enemy? [Edit: it does seem to, slowly - kudos.] At all ranges? I've found that the AI always thinks it's driving a tank, so it will try to turn sideways to manoeuvrer, etc.
Same with @GKJ's turret tank (it doesn't actually work with AI, unfortunately):
Also, the sideways fragment techs, although looking awesome deploying, definitely do just pick themselves up in the build beam and stay there.
But then it'll be good if the devs see that for themselves, and think about fixing this bug at the same time as implementing this new feature (if it happens).