In his project "Excelsior 1968", John Martz of Robot Johnny turned the photographs of every single person in his mother's 1968 Toronto High School yearbook into cartoons:
Last year I redrew my mother’s entire high school yearbook from 1968—over a thousand heads. Good cartooning, to me, is all about simplification, and this was a fun experiment in distilling each person’s likeness down to a simple cartoon version and learning to draw efficiently, with both speed and as few details as possible.
Link: Flickr Gallery | You can also buy the project in book form - via Laughing Squid