I originally had the idea of an animation-based TC called the "OmniCannon Mod" in which the player would look like he has the same weapon throughout the entire game, and whenever he switches weapons, the animation for switching weapons would play as if he pushes some buttons on the gun, and the barrel changes, a scope appears/retracts, etc.
But since there's no way to hide the alternate weapon mounted on your back (because of Soldat's blasted top-left corner pixel-based image-positioning system), this idea is up for grabs if anyone wants to go experiment. Good luck with working the Knife.