I have never seen a detachable face Double Din with a screen.Only thing I can think of is the old "fat face" pioneer's that where DD detachable face.And that was only a cd player.
Um, because the information that has to be sent from the brain to the LCD is to much for 5 pins, or how every conventional cd players work,
Also I think they are just for show more then function and they figure if you can afford one you can afford an alarm.
Plus if they made detachable ones they would have to spend the money researching it and researching all the proper technology for its use.
I would just want a detachable dace plate so i could store it inside my home, or even leave it in the car, just something to deter *** thieves from stealin stuff.