Oleana in Cambridge gets most of its produce from the farm run by the chef's husband. They get at least some of their meat locally as well. - for example River Rock beef. Also, they have a few vegetarian options as well as a fantastic vegetarian tasting menu.
I know that the Chef at Haley House Cafe in Dudley Square is very earth concious and particular about the ingredients she brings in. Their food is great and I believe they now have a Jazz brunch on Sunday that runs about $15 from what I hear.
Lumiere in West Newton is very eco-friendly, uses local and sustainable ingredients and the food is fantastic. Another in Western Mass is Route 7 bbq in Great Barrington Mass. who uses locally grown and sustainable food ingredients.