By touchpad I mean the magic trackpad. It large enough and would be cool to use instead ofnthe right analog stick on a 360 controller. Anyone try or is it possible?
While possible... most likely will be a bit frustrating vs a mouse. It will also depend on the type of game your planning to play. The FPS/Action/MMORPG games would be (imo) very difficult if not near impossible to keep up with the pace of things. A game such as a strategy/board game style, say Civ 5, or maybe Starcraft 2 might be possible, but again without using one for an extended period of time it's difficult to imagine it being anything nearly as precise and quick as what a tradition mouse does.
I use the MX revolution, and have for a few years. I have only messed with the Apple track-pad for probably 20 or 30 mins at a buddies house. Great device for general use, surfing and many non gaming tasks, however I can't see using it as a dedicated gaming device.