I always loved the idea of the reconfigurable LCD-like keyboard as portrayed in various versions of Star Trek and other sci-fi programs, but the first time I saw this concept, I knew I wouldn't like actually using it, because I am so enamored of tactile feedback on the keyboards I use.
I believe there will be LCD (or similar) user-interfaces in the future, but I think I have an idea to make them more tactile-friendly.
Some companies are working on a display method which will provide a screen which is flexible and bendable. My idea would require a flexible display with the bendability of a sheet of latex rubber, and it is reasonable to think that this point will be reached.
So, this flexible display would form the outer (user-accessed) layer of my keyboard, the underside of the display layer would have a grid of short pins, arranged in rows and columns, like the underside of current computer chips. The heads of the pins would be like nail-heads, but square, forming a sort of grid within the surface of the display, each approximately 1/16" square, or so (approx .15 cm). These pins would fit into a second layer, each pinhole having an electric locking mechanism strong enough to hold the pin down in place when engaged. Beneath this layer is a vacuum control pump.
When the display is reconfigured, the display is sucked against the pinhole grid board by the vacuum. The desired input display is shown on the display surface, and the pins under the borders between the buttons are locked down by the appropriate pinhole locks. Once the border pins are locked down, the remaining portions of the display are inflated, raising the keypads as drawn about an 1/8th of an inch (.3 cm) high off the pinhole board, forming the keys of the input display, which will physically mash down when pressed. Sensors embedded in the pinhole array detect contact, and the air pressure pushes back against the key so it pops back into place.
The square pinheads should form a grid which feels consistent when pressed, providing more uniformity of feel than if there were only air pressure, which would feel more like popping bubble wrap.