Passing on...
But why stop there then, if it's that easy? Need for other forms will most likely follow (fe. torus).
Thinking about ideal solution, 'Corona Light' having selective custom object (auto - calculating convex hull & optimizing it for fast "issue-free" rendering: no flicker or fireflies, soft shadows, hardly any caustics) would improve whole process. Development might take longer but, replacing a need for impostor lights and just create a mesh, add light and choose your mesh - done. Also, same principle can then be expanded on emissive material but would need extra work to calculate mesh with emissive channel only. This could save some serious time setting up lighting and give Corona further advantage...