You can virtually add anything you want in a Submod of yours, if you have the requested knowledge and skills, fundamental to start a project of this kind, and the allowance of the Edain Team if you want to use their material.
Keep in mind, though, that this is an Edain thread in an Edain board, and thus one shouldn't really discuss about possible other Submods, because it clearly has little to do with the topic and the Edain Team can't give official support to it.