Sunman Kwon has posted his concept phone design on yankodesign which is a wearable mobile phone with virtual keypad.

Description from the designer,

A wearable mobile device for enhanced chatting. It introduces a new wearable device that anyone can communicate with that is easier and lighter in mobile circumstances corresponding to the 3.5G, 4G communication standard. Human hand is the most basic communication method. For easier and simpler controls, it uses the instinctive input method “finger joint”. Excluding the thumb, each finger joint makes up twelve buttons, with “the knuckle button”, using the cell phone's 3X4 keypad, likely being the most popular input method.

Source via textually