Engadget has a story about the Display Keyboard that was already patented in 1998 by a Mr. Elkin Acevedo.
The Patent description is very much describing the Optimus OLED display keyboard designed by Art Lebedev.
No word yet if the patent holder is still trying to bring his Display keyboard to the market.
Engadget also reports about another display keyboard from a company called United Keys.
Well, it is great to see that there are more players in this new direction for keyboards.