Wouldn't it be easier to just do all shading and highlighting in the textures? As I recall, the 2 starwing games didn't feature any lighting. So if for example you have a cube, the side facing the sun would be the lightest, the side opposite of that would be the darkest, and the sides inbetween would be something in between.
If you do want something dynamic, you basically want to have everything "flat shaded" which means that all polygons have hard edges.