I only vaguely remember that the original creator of this model also have several other models with hypothetical refits, rebuilds. "Berlin" is said to be based on a private cruiser design from Schischau-Werke shipyard but i have my doubt since there's no sketch or blueprint of such ship, but of course there's no stopping KM interests into private projects, much like high-speed battlecruisers KW45 and KW50 or those wacky Atlantic bomber carrier destroyer and cruisers.