I recently put my rts engine as open-source. It is in development (50%) It can be found here using ogre3d. http://www.ogre3d.org/forums/viewtopic.php?f=11&t=83771 I want to make it easy to use with Unreal Engine and check if anyone want to join to create this rts library?
It would be fun and great to develop a better RTS-library with people here that we can use with Unreal Engine 4. Right now this rts engine is integrated with ogre3d but my plan is the separate the rts functionality from the 3d-renderer so it can easily be integrated with unreal engine.