Something along the line of the nonalcoholic beer and the vegetarian meat...

Jokes aside the double screen may not be a bad idea, however you would need the OS and every app to be adapted to handle this feature properly. Otherwise you will have screen content cut in pieces between screens or touch gestures where yo would have to jump the 'gap' with your fingers. At the end of the day this may be just apain to use even with an adapted SFOS or modified Android as you would run in incompatible apps every time.