Another idea.

Musical instruments should be "Stevie Wonder" compatible. How about a touch screen in which you select items by touch but activate them separately--e.g., by pushing an "enter" button or "double-clicking". There would be a keyboard mode in which the names of selected buttons were "announced" through headphones. A blind person or person with a keyboard in which the LCD backlight had failed or a person trying to operate the keyboard in sunlight could then take advantage of a keyboard dependent on touch-screen navigation.