Admittedly, I did not read this entire thread - twelve pages and counting. But, the original post was very interesting and I had a couple of thoughts on some points the poster raised. Forgive me if these have already been mentioned in 11 pages of replies that I didn't go through.
One of the concerns was - lithium batteries release carcinogenic fumes when heated.
While reading this forum, I have been vaping the entire time, and off-and-on most of the day. If any battery should be hot, it would be mine, right now. I checked my battery and rest of the assembly. I could not detect any heat at all. Not even warm.
The question should be - how hot do the batteries need to get before they start emitting hazardous fumes?
Will casual vaping result in sufficient heating of the batteries to generate fumes? Early anecdotal evidence seems to say "no". Having said that, a high-powered mod using a big bank of batteries that is cranking out more vapor than a school bus exhaust pipe, might heat up the batteries to the point where they become hot. But I honestly don't think the average vaporizer gets hot enough to make the batteries start belching out cancer-causing fumes. I use a modest eGo-T 650 battery and it doesn't appear to get hot during use. Perhaps during recharging when it's plugged into the charger? (but even then, your face isn't close to it while it's charging, so you wouldn't be inhaling fumes from it anyway).
Also, it bears mentioning (perhaps again) that the batteries in a device like the eGo-T are essentially a sealed disposable unit. When the batteries start to degrade and decline, the unit is typically replaced. So a unit in good proper working order should be less risky than an older unit with faulty batteries.
The whole idea of inhaling toxic fumes from hot vaporizer batteries just seems like the medical establishment taking the safe position on this - yes, hot lithium batteries can release bad fumes. Heck, any battery can get hot and it's never good when they do - your cellphone, your flashlight, or your car. But I personally think it is doubtful that a vaporizer like mine (small and relatively low-powered) is going to give me cancer any faster than smoking analog cigarettes or cigars.
Stay out of sunlight - it causes cancer.
Best regards and vape on,
MikeG