That's how the original design of what later would be know as Pz.Kpfw.Maus tank looked like. Pz.Kpfw.

VK 100.01(P), blueprint KV3381, June 4, 1942. The vehicle is still within 100 ton range, the "inflation" to infinity hasn't been started at that point. Armour was similar to VK.70.01(K), 149mm 15 cm KwK L/40 gun was suggested as main armament. In general it looked like German version of KV-5.

However, the vehicle just wasn't meant to stay in that weight class. On the 15 of May Adolf Hitler decided that weight would be increased to 120t class. Porsche guys had to follow.