If you took the LCD screen from a tablet. Segmented it into equally sized rectangles, and then added connection ports on the sides of each rectangle. Could you then separate and stack the rectangles on top of eachother to save space? And then fold it back out to create a tablet-sized screen again.
(Crude drawing of what I mean)
I think your limiting factor would be bezels, so there would be a small gap between the screens. Plus this would be a mechanical nightmare to make cheap and durable