Not so much a modding idea as it is a full conversion mod or idea for the devs to re-envision. This engine would be perfect for an old dos game I used to play called The Legacy: Realm of Terror by Microprose. It is almost exactly the same style of game play but in a more modern horror setting. Not sure where the rights for the game are though.
http://en.wikipedia.org/wiki/The_Legacy ... _of_Terror