Frank Zappa was doing something very similar with the Synclavier in the 80s (http://en.wikipedia.org/wiki/Synclavier).
He also has a piece called 'The Black Page' due to its density of notes on the page - http://en.wikipedia.org/wiki/The_Black_Page
Both together here: http://www.youtube.com/watch?v=UrOK98q_ILA&list=PL945B5DD750...