Anyone remember the horrendous Sprint Kyocera Echo dual screen phone? The phone had two screens that could be combined to form a larger screen. The main issue was that bezels of the two screens, when combined, were thick and was really distracting.
Fast forward to today and now we have phones that are thin with minuscule bezels. Imagine a slightly thicker Galaxy S8 with a second screen underneath the primary one that could be folded out to form a tablet sized device. The sides of the screens that would meet should be squared off a bit so there's a minimal gap in the middle. Maybe it could be a Note device with the S-Pen capabilities.
Would anyone be interested in such a device? Of course, thickness, weight and battery life would be concerns. Are screen, processor and battery technology far enough along to make this feasible and usable?