I might be developing a city game with a friend of mine using Unity Engine. Currently teaching myself the unity version C++ and figuring out the licenses for the engine. Essentially, the goal is to develop a open platform city builder using the principles of SC4, but in 3d. Good thing is that buildings could be created using 3ds Max and transferred to Unity.
We might use the Steam Greenlight when its finished and make it as a alpha game in development. Steam workshop could be a source for building lots and plops. Already have a friend of mine working on the music and me and another one gonna do the programming. Programming is a bitch though. So much syntax.. ughg
Instead of using the bastardized small plots in the new sim city, unity allows for large maps and procedurally generated. In the order of 10km by 10km or more. Goal is to develop a planet sized area that would function as the metropolitan area like in SC4. Also, with 3dsmax as a source, and the sc4 lot plugin which we acquired permission to use, this would have 1000's of structures.
Its a side project, but hey, who knows, could go big.