In the ship tree in between the Kuma and the Kongo there are plans for a CA and a BB. It would be nice to implement them sometime. Although the only BB/BC I know of that is still unused is the Amagi class and the Tosa class. Both classes were scrapped, after the Washington Naval Treaty, but the Kaga of the Tosa class, and the Akagi of the Amagi class became converted fleet carriers. Both classes were BCs planned to have 5x2 16in, but in game we could change it to 12.2in, since they were never completed you never know what they actually would have used. ;)