I just came across a magnificent (and stylish) interdisciplinary sustainable design practice, by the name of More Associates.
Using "design and research process to address social and environmental challenges" in practical ways. More "bring together sustainable design with emerging technologies and social innovation." Their current focus is on delivering carbon reduction and energy-literacy strategies across populations to produce widespread behaviour change and help transform markets toward carbon- and energy-efficiency.
More Associates is London based and was founded in 2002 by Luke Nicholson, Ben Pirt and Tom Williams.