I've been following the nebula threads and was thunderstruck by the comment nirougraphic made about rendering the same cloud using different lighting conditions and then blending it back - so I gave it a shot, just to see what would happen. I started with FrankB Dutch sky tgd and ended up making 4 versions where the only change was light directions and sun altitude. I varied the direction by 5 or 10 degrees, and the altitude by 2 degrees. Then I used PS to blend them all together using the brightest as a base and blending in the other layers and lowering their opacity. Then I repeated the blending but this time masked out the layer and brought in areas that had detail. I wish I were more PS skilled, the end result was interesting and had some of the same feel you might get from tone mapping, but this way you seem to have more control. But of course, the accuracy of the lighting ends up suffering, but I think you might get interesting cloud areas doing this.