Hi. Until we get a dedicated Corona Toon-shader, there is another "trick" that can actually make something like OP's picture quite easily. I've attached a picture with an example I made in a few minutes.
In the material override slot I put a material with an inverted (color correction) Corona Round Edges map used as diffuse map. Unfortunately Corona Round Edges map can't be used as mask in a blend or layer material, but it works fine inside a Color Correction in the diffuse slot. The overall scene-color is made by the sunlight, but it is also possible to use the color controls in the Color Correction map.
Hope it will soon be possible to use Corona Round Edges map as mask in maps and materials + Corona Scatter.
I've also attached the file (2014).