Powered Doors

Before I begin I'd like to say that the following idea would be very useful for creating and using airlock systems!
It would be very cool if we could get lights that could change between red and green that could also connect to doors via redstone (ie pressure plate) to indicate whether the door(s) is open or closed with the ability to lock the door(s) until the light turns green. Likewise this could also be achieved by the door(s) itself changing colours to indicate status. I have started installing airlock systems in certain places as a result of all the water encountered in those areas so I use these airlocks to keep the water at bay.