Ultimately, I would love to be able to make a RMH to fit on an area just 1ft by 3ft, and if that weren't tricky enough, leaving enough space for chimney sweeping, in the middle!
Why so small? Because that's the size of the fireplaces/hearths in my house.
I have been thinking: maybe rockety part on one side with a thermal mass and winding chimney on the other, but have just realised that the burn tunnel needs to be longer than the space available on one side.
I'm not one to give up thinking abotu a technical challenge easily, so I guess im posting to get told, by someone who knows for sure, that it's a non-starter.