Oh, no offence meant or taken, Franco, but I've built and use simple generators of various kinds, for many years. Not ideas, but working tools. The "ideas" have already been invented for this kind of thing. How practical they are is another question. One of my passions is amateur radio (ham radio operator)from the back country and alternate power sources are part of the game. That chip I referenced simply needs to be placed on the side of a pot of boiling water, and presto...you have voltage, but not much current. Enough to drive a small fan and stoke your fire. Stick that chip to the side of a Sierra stove and you ditch the battery. I noted the Biolite folks aren't publishing their power producing specifications, that I could find, but I know something about thermoelectric and the chip I referenced is likely the one they use, or similar. However, I hope their stove is a great success and I bet you see it evolve if it takes off. It's a good turn-key product...when it becomes a product, for "those that don't have the knowledge or tools." My nature is to build my own, and have. DIY is an industry unto itself, Franco.
One of the sections of this forum is "make your own gear", which I personally do more than buy "products". I have a couple of plans in that section that people have built and have spread around the internet. I'm not interested in offering products for sale, but know many people who share a passion for 'make your own gear'. Since by brain has been chewing on this "camp power" idea, I'm now thinking up a tiny but efficient (and lightweight) generator, from off-the-shelf parts, that can be coupled to a small collapsible wind mill, or steam turbine...but you won't see a "product" offered.
In fact, I doubt I'd hike with such a mess unless radio operation is the goal.
Solar, thermoelectric, wind, steam, static (what's that? ), are all possibilities....how practical, is the question. I'll say this...I'm not wild about burning campgas or firewood (illegal in most parks) to charge my iphone or radio batts. Clean burning fire methods have been around for centuries...nothing new there.