The Samsung Soul tries, and largely succeeds at making a touchscreen 5 way navpad. Like the Maximus Optimus keyboard, the controller is backlit by an OLED screen (this one is a two colour deal) that changes icons depending on the context:
In the media player, you get FF/RW and play/pause controls; in the calculator, you get plus, minus, subtract and divide buttons. The soul patch (my name) even vibrates when you click it, thanks to the same Immersion tech found in Playstation and Wii rumble controllers. Congrats to Samsung in making a touch UI that overcomes some of the shortcomings of touchscreen controls in a nice looking package.