Art.Lebedev (makers of the OLED optimus keyboard) has a new prototype called Optimus Tactus. The idea is to have one large OLED display, which is touch sensitive.

This way you can change not only individual keys, but to completely change the keyboard's layout.

Kyulux - Hyperfluoresence OLED emittersKyulux - Hyperfluoresence OLED emitters