Vivian Maier's book is on pre-order. She did a lot of 6X6 in Chicago and elsewhere in the 60's thru, I believe up to, the 90's....her book comes out Nov 11, 2011. After seeing her work at the Chicago show, I was struck by her amazing composition, intimate view of Chicago people and people elsewhere.

This might just fit the bill...

http://www.vivianmaier.com/book/