Ahh, the things you find when you have 10 minutes to kill on the internet.

I found a website devoted to low tech solutions.

This article on Oven Stoves was intriguing; I like how it covered both advantages and disadvantages; very evenhanded.
I bring it up, as it seems A) very green B) very durable C) run forever with no outside help.

I do not have one, I do not not sell them, I make no money from this....

http://www.lowtechmagazine.com/2008/12/tile-stoves.html