Barring any additional rendering/changes/adjustments, I'm going to call this done and useable for beginning my Zbrush sculpt sketch and base mesh construction. @Snader: I'm keeping the smokestacks. I need the engineer imagery!!!
Not seeing a whole lot of color 'schemes'. I just see the same scheme over and over with a single color changed. I also think you should work a bit more with stronger, simpler color planes, as yours right now are quite detailed, which makes them rather noisy at smaller sizes. Notice how from your gray-scale sketches the…