Maxis is finally making good on their promise to allow SimCity modding. There is a thread on the SimCity EA Forums where the developers are soliciting advice from game modders, aiming to foster a thriving community of hobby artists creating custom buildings for the game.[ref]
In loosely related news, SimCity modder Oppie has successfully imported a custom 3D model into the game. Previously this wasn’t possible as SimCity would detect the abnormality and trigger a rollback. Not only has Oppie managed to get the game to render his 3D models, but he’s also successfully circumvented the rollback system (Props to ProcsKalone for this little innovation).
One way or another, SimCity mods are happening.