From 9to5mac
According to screenshots submitted to us by iOS specialists Nick Frey and Sonny Dickson, the taller iPhone display will provide slightly larger keyboard keys. As you can see in the image above, the keys for the longer iPhone screen are slightly larger and stretched out. However, the keyboard itself does not get stretched from side to side of the display, noting that this is not a simple keyboard stretch for the higher resolution, but an intentionally tweaked keyboard design.
http://9to5mac.com/2012/08/09/how-t...ller-display-may-position-landscape-keyboard/
http://9to5mac.files.wordpress.com/2012/08/keyboard-comparison1.png