PhotographyBay found an interesting patent for a touchscreen DSLR filed by Canon. No, you will not change the menu with your nose while shooting - the iPhone works in a similar way: it has a sensor that turns off the touchscreen when you get it close to your face. Here is the suggested solution from Canon:
"Specifically, the camera is supposed to allow users to register their dominant eye. The photographer will input whether it is the left or right eye. Then the camera will detect the registered eye when it is brought to the viewfinder. At that point, the camera will disable a portion of the touchscreen that would likely be touched by your face and, therefore, prevent any setting changes. Also, note that the patent covers the possibility that the camera may automatically detect which eye is brought to the viewfinder and disable the appropriate portion of the LCD."
