Lighting tool for artists
There may already be something like this out there, but how about an app and/or program that allows one to create or upload a 3d shape, and experiment with different lighting sources on it? They could pick the direction the light source(s) are coming from, along with the color, intensity, and size of the lighting. The texture/reflectiveness of the target object could also be modified. This would be an invaluable resource for people who like to draw/paint from imagination, but need some additional reference.
Reward: Satisfaction of having a good point of reference.