We don't think it's doable with Wii games, but Nintendont does it by running GameCube games in a different way that allows for controller emulation.
Also, the classic controllers have no accelerometers or IR sensors, so there would have to be buttons specially bound to Wiimote movements and a thumbstick would have to control where the Wii cursor is pointing in games that required them, not unlike what Dolphin does.