Okay, so I decided to come back to this thread after some time to figure out what I wanted to do and other works (I don't really consider this a dead thread because I created it and am still using it). I still haven't figured out exactly how to make anything that looks exactly like Coruscant, but decided that it would probably be best to create something loosely based off of it. To get the city image, I read over the Photoshop tutorial provided by Lance McKnight and used the idea of city lights to create a basis for a look. But instead of using Photoshop (because I don't have it) I used AlphaSpace and Grim Color Reaper to extract the lighting from the images that I wanted to use. I also took the advice of Delpart and played around with the Shape3D settings. I also coupled the design with Goonfella's Realistic Earth model and Sozo's Glow model. The colors I chose for the night time lighting are a reflection of what I'd like that particular species to prefer, which seems to dominate the image. But, for the sake of the idea as a whole, I decided to leave it. So, here is the image I created.
If you'd like to see a larger version: City Planet