You can "hack" in an extra 360V battery and add range to the Leaf with an auxiliary 360V battery of some sort..
Of course that can be super expensive and even heavy.
I was thinking of taking a wrecked Leaf, harvesting the battery, putting it on a trailer, figure out which pin opens the contactors, integrate that and the high voltage lines to the Leaf's, and violà! Not only would it be cheap (I'm seeing wrecked Leafs with working batteries for less than $1,000!) but it would also extend the range farther than simply putting in a new battery.
But I think I'm leaning towards aeromodding the Leaf instead. According to all my calculations, I should be able to increase highway range by 35% with as little as $400 in aerodynamic improvements (basically following the AeroCivic design.)
2013 SL, 40,000 miles, 12 bars.