Thanks for the The barrel method in the first two links is incredibly crude -- not much more than what I'm doing now. It may work with grasses, but I suspect you'd get a lot of ash if you used wood. The main problem is that you create a lot of noxious smoke and gases (that "closed-in fire" smell), and you waste the potential heat source.

But I'm blown away by the LuciaStove. It burns clean. It lets you use the gasification products for heating. This is exactly what I want to build, except on a larger scale (and possibly with a series of removable fuel "cartridges" for continuous operation).

Here's a good rundown on the LuciaStove, its components and principles (w/subtitles):
http://www.youtube.com/watch?v=QsH_Gh-n2Mg