There's more to a roadster than just cutting the roof off. Because the Leaf (like just about every modern car that isn't an SUV or pickup truck) is unibody construction, removing the roof means you have to substitute the loss of structural integrity with additional bracing. That would make the already-portly Leaf even heavier, which means it won't handle as well even if you beef up the suspension. That will also drive up costs, so it's not as cheap as you would think.
If the additional bracing is insufficient, at best you will have quality issues, since panels and other components will slowly work themselves loose from all the chassis flexing. If it's really bad, it may not pass crash testing standards.
Blue Ocean 2012 Leaf SV, lost that 1st bar at 34 months/26,435 miles. Lease returned 2 months later. Final LeafStat figures: 225 Gids, 17.44 kWH, SOC 91.89%, SOH 82.36%, 69.49% HX, 54.57 Ahr, battery temp 61.8 F.
Now driving a 2015 VW eGolf SEL.