There are some wonderful comprehensive overviews of clean cooking stoves on the internet.
These are a few great resources.
and an excellent comprehensive report of Microgasification Technology compiled by Christa Roth
Micro Gasification Cooking with Gas from Biomass (pdf)
Global Alliance for Clean Cookstoves Catalog of Clean Stoves
and the Partnership for Clean Indoor Air report on clean cooking stove types (pdf):
Dr TLUD - Comprehensive TLUD resource