Unfortunately there is nothing for the 2012 model and still, 40lt is 2 jerry cans so the cheaper option still wins IMO.
I was looking at the poly tanks made that sit along the sides to the wheel arch but they take the room I want to use for other stuff. Surely there is a ready made tank that will bolt up under a tub???
My previous setup was spot on (tray back), 130lt water tank/pump and a 60lt aux diesel tank. Sold it as it was too wide and long so have gone back to tub and canopy.
Might look into getting something custom made and attach to the base of the tub...