Found this lovely rocket stove adaptation through the forums at Permies.com. I believe the burn chamber in this picture is below the cooking pots. Behind the hearth, you can see the warming bench. The exhaust pipes are located within the bench and warm the thermal mass that comprises the bench. My understanding is that you could heat a space like this with less than a cord of wood per winter using a rocket stove like this one. Fantastic.
Much more about rocket stoves here: http://www.richsoil.com/rocket-stove-mass-heater.jsp
The local expert around here on rocket stoves is Nate Ayres at http://www.chiwarapermaculture.com/