Concept / paintover

What little spare time I've had these past 6 months have mostly gone into getting on top of things as far as the full creature pipeline goes. This has entailed a lot of time trying to learn about vray, proxies, displacement maps, SSS shaders, comping render passes in Nuke and that whole bag of fun. As a part of this I've been playing around with a giant turtle scene, where the idea was to have a city under a glass dome on top of its back.
However, after trying for a long time to get it to look right, I've decided I did not much care for how the city itself came out looking. So, back to the drawing board. The turtle itself is pretty much done. I did a quick render and painted over it to come up with some new ideas. Those tiny submarine thingies are also built already, just need to redo the city and build a mountain. Sounds easy enough, right?

The sketch was done in 5 minutes and looks like it as well. But hopefuly you get the idea.