I really like the concept of participatory farms. Some CSA farms are like that, so too are some set ups where animals (sheep, chicken, etc) are owned and managed in part by the city person.
Several cow share operations, like this one in Chilliwack B.C. have come under scrutiny and legal battles over sale of raw milk.
Here is a farm that is bringing grain growing opportunities to folks on Vancouver Island.
"Brock McLeod and Heather Walker will teach you how to start your own wheat field, even if you live in the heart of the city. Using a plot on their farm, expertise and tools, participants will produce enough of the grain of their choice for bread the year through. From The Tyee