I have found a very interesting web site of a family of 5 in Pasadena, California, who are practicing urban agriculture on their typical lot in an older neighborhood (house was built in 1917).
They started in 1985, there are great before and after pictures of their urban homestead. They have 3,900 square feet under cultivation (1300 sq ft of this is in containers) on a 55′ x 132′ lot, which is about 8700 square feet; the house is 1500 sq feet and the garage/driveway is 1300 sq ft.
From April 20 to November 20 this year, they harvested 2054 pounds of food plus 313 ears of corn. See also their statistics page with lots of resources and links, plus pictures of their gardens.