Most small Rocket stoves that are built in a 5 gal bucket are used for cooking, like the one this
video demonstrates.
http://www.youtube.com/watch?v=PeKcb-Fw-bo&feature=related
I build one of these and it works well. I suppose that you could try and modify this design, instead of ashes inside to hold the heat in use cobb to retain the heat and radiate it into the room. Making a cobb piller straight up with the exaust pipe in it would also help. But this straight design does not give you the advantage of the down draft system used in the large units. Since it is an open fire, and I would not want to burn up in the small house I would not put it on a table. It
should be mounted solidly on the floor. I think you can play with different designs and see what works for you, you are not heating a large area. Paul has a
thread on here about his experiments with a " small " portable rocket mass stove. You can read his experiance and learn from his mistakes. No need to reinvent the wheel. The unit he made was much bigger than what you are talking about, but you can still learn
alot there. The main thing with a
Rocket Mass Heater is the MASS. That is what holds the intence heat created by the rocket fire in the stove. With out much mass I don't see how you will heat even a small cabin unless you fire alot. Good luck with your
project.