This article describes a custom creation, custom theme, or other fan material, made by a Brickipedia contributor. It has never been, is not, and will not be officially released.
The Power Functions Joystick Controller would be an 11 x 5 controller with a D-Pad sort input on the left, for basic movement, and two buttons on the right to control other functions, such as Linear Actuators.
It would be a 2-Channel Device, so would work best with the Power Functions S-Receiver.
(Pictures soon, need to draw them!)