As a long time Battletech player (since 1988), I have never seen a 'mech with a turret or a 360 degree torso twist. Not even the Raven or Annihilator. However, there are several designs that have "extended" torso twist, like the Urbanmech, the Wasp, the Exterminator, and several others. However, there are also several designs that have no twist like the Locust and the Jenner. I think if there were a mod that included one, it would need to include the other as well.