Treaty loopholes and a giant pre-dreadnought

What unusual warship would you design if a treaty loophole allowed it?

A very large pre-dreadnought could exploit an exemption from dreadnought limits, using four 18-inch main guns and 16-inch wing-turret secondaries to retain a mixed battery.

If treaty limits applied specifically to dreadnoughts, a mixed-battery pre-dreadnought could fall outside them. The proposed ship grows beyond 30,000 tons while preserving the older division between main and secondary armament. Four 18-inch guns provide the main battery, with 16-inch guns in wing turrets as secondaries. A Lord Nelson-style arrangement could give a broadside of four guns of each calibre. Its size and complexity follow from exploiting the classification used by the hypothetical treaty.