While it's fascinating to see yet another variation on the theme, I see the market for the Thermette as somewhat different than that for the Kelly and Storm kettles. With the extra bulk and weight, I think backpacking use is pretty much ruled out. This is a car-camping stove, or a home/cabin/disaster/survival stove, maybe in somewhat the same niche as the 18-lb "Volcano" stove that claims to cook for a family of 5 for a year on 300 lb of charcoal brickettes (or "briquettes", if you prefer, though I've never seen a building made of "briques").

The lack of a bottom would seem to be a drawback, but maybe if you routinely car-camp in areas with fire pits, it's easier just to pick it up and leave the ashes behind than it is to clean out a pan.. and it's probably still a much faster way to get morning coffee and/or tea than building a big fire. The lack of a bottom, and of a top "flare" on the fire chamber might have one other advantage- it means that it's much less likely to slosh or boil over and douse it's own fire.

For a long-term stay-at-home survival scenario, say a prolonged depression, or full wartime, I can certainly see a use for this. There's no shortage of tree debris in our area for fuel (I pay a company now to haul it away periodically), and long-term water purification would use a LOT of fuel. You could stand the Thermette up in the Weber grill, for that matter, and have a semi-permanent operation going on the back deck. For portability, where 95 percent of the use is for boling water (for freeze-dried foods, or to heat MREs, or whatever), the Kelly and Storm are clearly superior.. but in a truly long-haul scenario, the cooking versatility of the Thermette would come into it's own.

On the other hand, a small aperture on a copper boler brings another possibility to mind- it would be relatively easy to connect that small outlet to a condenser. This very efficient, copper boiler could pretty easily become the basis for a mini-still. :-)