Mike,
the last one is no windowlight looks better for me... better contrast.. maybe a this distance and scale the board lights shouldn't be seen so bright? Or maybe be slightely colored?
Also, your material could be too much "diffuse":
in a house interior, it is normal to see the red bleeding of the carpet on the wall..
Here, it seems the main tower is quite a lot lit from the front, by the light diffusion comming from areas directly lit by the sun.
Maybe, because of the light loosing intensity with distance or because of it's scattering, diffuse light should be less visible (more contrast). At this scale, it might be difficult to adjust roughness and reflectance acurately because of the lack of mico-details.
Have you used almost perfect specular mirors or glass? it would be cool once animated to see the movement of sunlight reflected caustics on the ship (like a building's windows in he sun does on the building in front of it in the shadow).. Maybe for a closer view
Do you have any -ml images or movie for the ship? It would be very instructive!
Amazing image and still progressing! I hope we'll see your starwars version once released!