Fractured State is an RTS game being developed in the Unity Engine. The primary goal, besides creating an engaging and fun strategy game, is to build a framework on top of the engine that will allow modders and map authors to create content that is loaded at run time into the engine. This is achieved primarily through XML config files that are serialized and used as a foundation for objects ingame. I've spent the past 6 weeks or so laying out the foundation for the framework (loading mod configuration files, exception handling, etc) as well as beginning work on the Map Editor. Here are a couple of shots of the progress thus far.
You can get more detailed information by reading my blog at FracturedState.net where you can also join the discussion on the message boards.
Are there any features that you'd love to see in a moddable RTS? Leave it in a comment!