Nintendo Japan has announced a new controller for the Nintendo Wii but they haven"t yet made the announcement that will be avaliable for the rest of the world. The new controller is based on the old "Classic Controller" but is called "Classic Controller Pro" it features extra shoulder buttons and the space between the thumb sticks and the hand grips is a bit larger, to quote Eurogamer "Specifically, the Pro gains 32.5mm vertically, 10.3mm horizontally and 29mm in depth.".
As mentioned before the controller hasn"t been announced for a worldwide release but expect it to hit the stores in Japan in the Summer.