Sony may be covering all your controller needs soon with a universal controller. Sony filed a patent for a universal controller a few years ago which just recently appeared online. The controller would work with a variety of game consoles and, using a built in LCD touch screen, would create a display of the button layout of another controller.
“This document describes an adaptable or universal game controller which can be used to emulate the controllers of popular game consoles, such as, without limitation, the PlayStation.TM. made by Sony, a controller made by Nintendo, X-box.TM. game controllers made by Microsoft, Amiga CD-32.TM. controllers, Atari Jaguar.TM. controllers, Gravis Gamepad.TM. controllers, Sega controllers, and Turbographics controllers, one or more of which terms may be subject to trademark protection. For ease of exposition trademark symbols will not be further used herein.”
The patent also lists that the controller will have built in rumble and a built in speaker.
I’m not sure how well touchscreens works as a complete controller, but it is a interesting idea. You could have a Virtual Console like service that wouldn’t require players to adapt to new controls on a new controller.
Would you be willing to do all your gaming with a touch screen controller?