There's been a lot of talk about VoiceOver on the iPhone 3G S... and so there should be. I suspect (and others seem to concur) that Apple's model for touch screen accessibility ought to be quite useable under most circumstances, but that typing on the touch screen keyboard could be rather challenging, perhaps the most challenging aspect of the interface.
Thinking about this, I had a brainwave: perhaps a Braille touch screen keyboard could be a nicer solution for blind users. A Braille keyboard doesn't require you to shift your fingers horizontally or vertically, which eliminates the challenge of finding characters. Instead, you only need to raise or lower your fingers in various combinations. I'm guessing that the multi-touch touch screen should be able to detect these combinations. I can't remember how big the touch screen on the iPhone is, but I suspect it is probably large enough to allow for the fingers to be placed in Braille typing formation. I can't type as fast on a braille keyboard as I can on a QWERTY keyboard, but I'm a hell of a lot faster on a Braille keyboard than on a phone keypad. In fact, I'm wondering whether this method of input would actually be faster (assuming a proficient Braille typist) than a sighted user using the normal touch screen keyboard.
Surely I'm not the first to wonder about this... or is this really a new idea?