Space Sim Central has hosted a short developer Q&A section that touches many development areas ranging from single-player campaign, branching missions, up to multiplayer and modding in the upcoming space sim Heresy War.
Here's a short quote from the Q&A session:
SSC wrote: Looks like Heresy War will ship with some modding tools. Can you give us a run down on what you will be able to change or do with the tools you provide?
We're going to have at least a level editor, model viewer , model compiler and effect editor. Our scripts can be edited with any text editor, so nothing spectacular is needed here. With these tools players can create new models, ships, weapons, levels, gameplay modes, menus. Pretty much everything that you will see in the single and multiplayer levels can be recreated by the community without the need to recompile the game executables or libraries.
You can find it by following this link