hardware, and parts that even recent models of nav systems use are proprietary-- many times, they won't even give up the basic control structure to anyone without signing all sorts of legal papers..
of course, if you had all the time, money, and bill gates for programming the system, then i think it is possible, but not for the average hobbist..
i don't know what other options your looking for..
i do not believe there is any way to add screens to the factory nav system.
lockpick is a different type of solution-- it allows you to watch movies while in motion, and also unlock other functionality that is normally disabled.
these devices serve 2 different functions:
mimics is intended to be used with a iphone where you can generate the screen--the mimics only deciphers the touch signal, and doesn't do anything more-- so the iphone screen would be shown on your lilliput screen, which would be connected to the mimics unit to allow you to press buttons-- you are dealing with the iphone interface.
lockpick can control your ipod/phone, but does not give you access to the actual ipod/phone interface. it grabs the media off of the device, and allows you to play it.