sierra - yes they are expensive, but are meant for seriously cold climates and are based on the masonry model of a large brick mass, often tiled (in this case with soapstone) - and an internal metal fire box, which was used in Middle to Northern Europe, including Russia - they also contain a number of internal chambers for a further burn-off of gases (and the resulting heat gain) to eventually escape as an almost clean gas. The soapstone holds the heat over-night. Some of the more elaborate Tulikivi stoves have a similar internal chamber set-up for maximium heat gain and clean gas emission. They are expensive, though.
I had thought of simply lining my existing fireplace with that special brick used for the inside of blast furnaces, then tiling it and just putting an ordinary metal stove in it - but they are simply too ugly, hence my search further afield. I now use solar (electric heaters, no electricity cost in summer, but more in winter) - and some air conditioning, but the warmth of a 'real' stove is something I still crave, but find that I hardly ever get sick, unlike my 'cousins in the valley' - so maybe we are meant to freeze every so often - haha.
Coming back to the proposed metal sheeting for the secondary burn; seems that model could stand some improvement, though; I am planning to move from here, so the question of 'stoves' will come up again.
