I don't mean any offense- but I'm less than impressed with so called "wood gas" stoves that produce tall yellow flames. A true wood gas flame is blue(ish) more resembling a natural gas flame. These stoves, in my humble opinion, are what I'd consider expensive (at least in the case of the bush buddy), well built, and slightly more efficient, hobo stoves...
I chimed in a discussion on the subject over on this thread- http://www.backpacking.net/forum/ubbthreads.php?ubb=showflat&Number=145636#Post145636 and posted some pics of my quest for the blue wood gas flame...
In short, I don't think it's really possible in a backpacking style tin can stove...too much heat loss. In reality, the stoves need insulated combustion chambers, which I'm still trying to figure out a simple clean, easy to make, design.
Just my $0.02