This is a very interesting thread. Thanks to djoss' work, there are several direct drive MT-G2 lights documented in this thread:
So if I'm following this conversation correctly, I should be able to connect 2S Moli IMR26700 cells to a well heat sinked MT-G2 without damaging the emitter? Brand new, these cells can deliver 40+ amps continuous.
And my unprotected Panasonic 18650s can do +25 amps short circuit, yet only do a bit over 5 amps direct drive into a MTG2. The current delivered will depend on the voltage present at the LED under load.
OK Comfy. You convinced me. I will try it. If I don't blow my emitter (that sounds funny), I will thank you for your contributions to this thread. If I do blow my emitter, may the lumen gods forever curse you and your lights.
Use one for fins and the other for the cookies to eat while taking a break. 
I had overlooked that thread, nice collection of mods sofar , thanks for the link :-) .
As for using 2 x 26700 IMR cells, I'm sure because of the bigger size they sag less than 18650's, so they likely will deliver more than the 8.5 amps through your mt-g2, the question is how many more...
Oh, btw, at 8 amps you are at 85% of the max output (that is: if the heatsinking is done well), is there any point to go higher??? 
Wrong! Anodizing (clear or black) increases the emissivity of aluminum. Black is best.
http://www.infrared-thermography.com/material.htm
Also, brass is a horrible conductor of heat. Aluminum spanks its ass… it’s at least twice as good. And copper is twice as good as aluminum. I’ll take an aluminum pill/thermal compound any time over something soldered to brass.
Thanks TP, I had wondered at that since anodizing dramatically increases the sufface porosity and hence the surface area over polished aluminum.
Yes… shiny, smooth, and reflective are the enemies of efficient thermal radiation.
Then the opposite is true. Hence lapping.
As a matter of fact, every radiant heater I’ve ever seen has been shiny and smooth. Wonder why that is?
Surfaces in contact transfer heat by conduction, not radiation (BTW, heat radiates at a rate proportional to the FOURTH power of the temperature difference, and another fun fact… the noise of a turbulent airflow increases at the EIGHTH power of the velocity)
Radiant heaters have a shiny reflector because they are trying to reflect the heat from the heating element, not radiate absorbed heat.
Lapping enhances surface contact maximizing transmission. Radiation depends on maximizing surface area. Exactly why Alu radiates better than Cu I’ve no idea.
Where he bought quite a few oil filled radiant heaters, thinking that they would save on running the house heater. They gobble up electricity and radiate small amounts of heat in a confined area. Seemed pretty wasteful to me. They were indeed designed to radiate the heat of the hot oil filling them, and without fail they were smooth glossy painted surfaces. Attributable to poor design, no doubt. Inevitably the temp sensor would fail and they would sit and heat up to extremely hot temperatures, ready to burst and dump overheated oil in the house. They now sit in the storage shed but don’t let it get too cold this winter or his 85 year old self will drag em all back into the house!
This makes me wonder, we run tests and hold instruments close to a stationary light and figure we’ve got it all on paper. But when we use a light we are generally moving around handholding the body and of course most of the time it’s night out and the temps are cooler. So the ambient conditions when in use are almost always going to be more favorable to heat absorption than in testing, true? Will this make a big difference or mostly minimal difference? Obviously, going out on a 90º Texas summer night as compared to a sub zero gusty stormy winter night up North would have drastic differences in the lights operation. But just how effective are the fins on the heads of most of our lights, when the inner pill is seldom made as a press fit unit to maximize thermal conductivity. Most of the lights I’ve bought actually have dead air space between the inner finned areas and the aluminum pill conducting all the heat. Can we do more than wrapping the pill in aluminum to optimize the fins inherent to the outer head?
What if that contact was optimized, then a hole was bored through say 2 sides…off center of course so nothing internal would be interfered with…and an aluminum tube was ran through it and either left slightly protruding or shaped for aesthetics to fit cleanly into the lines of the light? Would this then allow an air path to conduct the heat straight away from the core? A heat pipe, if you will? Or would this too be inefficient without air directed through it?
The heat finds it copasetic and rewards us with happy escapes!
8)
<—-in need of pain meds, please forgive