While 10000 lumens is within the realm of possiblity with 12 XM-L T6's, there is another problem that is almost certain to prevent you from getting to 10000 lumens. The T6 at that drive level is about 90 lumens per watt, and the driver is guaranteed to be less than 100% efficient. Bottom line is you probably need about 120 watts in to the driver to reach 10,000 lumens output. That creates a huge heat dissipation and heat transfer problem for the LED's
If you use standard 18650@3100mAh, you are limited to about 12 watts per battery, so you would need 10 18650's to get to 120 watts. If use IMR cells, they can put out a lot more power, but the energy density is considerably lower. You can get 120 watts out 6 IMR 18650's, but your run time will be on the order of 25 minutes before the batteries are fully discharged, that is if the LED's aren't already fried trying to dissipate the power.
Many of the lesser known brand lights on ebay deliver far less than the claimed lumen output. If you using standard 3100mAh 18650, and you have 6 of them, the total output is unlikely to exceed about 6500 lumens.
