Though a "real" tank project and not really a "whif", this beauty is a kit-bash worthy of whiffers.
Seen in "Fine Scale Modeler' magazine, this heavy tank was an enlarged M26 Pershing hoping to counteract the German giants appearing on the WWII battlefield. The modeler took two Pershings and stretched it and scratchbuilt many pieces.
Anyway, thought you armor buffs might like it!