Nintendo has recently applied for a patent on a peripheral device for the Wii that is similar to an inflatable kiddie horse, complete with a set of reins. It is a small inflatable cushion reminiscent of the “Hoppity Hop” that has a dock for the Wii remote. When you bounce or move, the controller registers the movement. Nintendo cites in their patent, the ability to ride bulls, whales, dragons, griffons, unicorns and giant eagles through the use of the inflatable cushion.
Although it is only just a patent with no guarantee of production, I really, really hope they make them if only for the entertainment value - think of all the YouTube videos just begging to be made