I read your note and admire you for admitting your bias. I hope you will not mind if I suggest a few ideas that reflect my pro- biochar bias.
You write: 'There is a central process involved (fermentation and distillation / combustion) but the goals are almost completely opposite (clean complete combustion into gas / smoky pyrolization with non-burned byproducts). And as a rocket stove enthusiast, I am somewhat biased to regard biochar as... well, maybe slightly more attractive than slug bait."
If you were to make a small TLUD, perhaps as shown in the Biochar ACtivity Kit", <http://www.greaterdemocracy.org/archives/1316>
; you would see for yourself that even a simple TLUD in a 15 oz can is NOT very smokey. Quite the opposite. A well tuned device burns pyrolytic gases much cleaner than burning solid biomass -- with many fewer nasty by-products than your average wood stove. Particulate matter, especially at the micron level, in the exhaust stream of combustion systems is always an issue. Please watch this video to see how smoke free pyrolysis can be: <http://www.youtube.com/watch?v=Kg95KYrH8PI>
. Further, the byproduct, charcoal, is not unburned at all. Burning = combustion. Pyrolysis is NOT combustion. Rather, the biochar is the harvest of carbon that photosynthesis has pulled from the atmosphere. It also converts the carbon from easily oxidized organic carbon to difficult to oxidize elemental carbon. It is this conversion that give biochar its longevity in the soil. It is this long residence time in the soil, the retardation of the natural carbon cycle, that leads many to say that biochar is carbon negative. Every one pound of biochar put in the ground has removed 3 pounds of CO2 from the atmosphere. This removal of CO2 from the atmosphere is a good thing. Why not embrace it?
Fundamentally, a TLUD is not a Rocket Stove. Nor is a retort a rocket stove. A well designed TLUD, for example, could be used to provide the thermal energy to heat a thermal mass as in a RTM heater. The difference is that it would take more feedstock to offset the carbon being harvested for use as a soil amendement. This extra biomass improves the efficiency of the systems removal of CO2 from the atmosphere. And a TLUD powering a thermal mass heater would be carbon negative, which the Rocket Stove is not. In this way the biomass, perhaps wood, would have at least three functions in the stack: heating your home, providing carbon for your garden, and lessening the CO2 load in the atmosphere. What is not to like?
A consideration I do not see any mention of is simply this: what would be the impact on forests if millions of people started to use large amounts of wood in a HugelKultur raised bed garden? Further, it would appear that the wood and its carbon will need to be restored every few decades. If a mix of biochar and compost were used instead, it would deliver benefits for many times longer than the use of simple raw biomass. Thus the use of biochar and compost would extend the use of the garden without the need for regular infusions of woody biomass. Evidence: the vitality of centuries old terra pretta.
Note: Biochar is sterile and empty when it comes out of the TLUD or retort. It is important to "charge" it with nutrients, minerals, water, and microbes before adding it to your soil. Mixing it with good compost, perhaps with some sea salts, is a great way to "charge" the biochar.
In the above scenario, it is important to understand that the biochar does not have to be made from wood. I have made excellent biochar from grass. Others have done so with many other materials, waste streams, including paper and sewage sludge.
In the end, we both want the same thing: A new world that is better than simply sustainable. Raised beds are great. Thermal mass heaters are great. Compost is great. Being carbon negative is certainly attractive. Food, water and energy security are all highly valuable goals. I suspect we also agree that it is important to do more with less, thus I am sure you too support energy positive housing.
Finally, in the end, the use of biomass for energy is at best a bridge to a future that has found better ways to get the job done. And I do NOT mean nukes