Cerberus

This was a long dreaded and suspected ship from the Threat Files, where the Klingons, based on three booms and pumwI-based Stardrive, with some scrap and spare parts hanging around for 7 years, were going to build a larger Battleship, one of 15 Super Battleship Projects, one which made use of three Romulan Plasma Weapons and many swivel-mount Photon Torpedo Tubes to pound the target base or station's shields, and then deploy it's troops, the vessels theorized as being accompanied by two L-9Fs and 4 K-27Fs.

Despite all the worrying and theorizing, none were actually built, although the vessel was one of the more fascinating imagined vessels in the Simulator.