Artificial planets... does that mean they can have a population and such
Unfortunately not, due to the restraints of GC2 modability, they are merely more expensive and more powerful Econ Starbases that look like planets.
also, how'd you mod the SB's appearance? i don't remember seeing that in any of the modding guides i've seen. if nothing else, i can just poke around the files when i get home.
I actually created a sphere in a 3D modelling program, textured it with a planet texture and named it after the original model file.