Actually, thats what i'm planning on doing too. If you get the non-motorised screen from DigitalWW, it looks fairly plain folded in. I will be using double sided tape to hold a flat black panel over it so that you cant see anything. I doubt you will even notice the panel when its folded out (the panel will be horizontal to your plane of vision then)
I also have a Kenwood MASK headunit, so that will look like just a flat panel underneath it as well... Completely stealth!