Yes I have blown an XM-L direct driving it with an IMR 18650. It will shoot up to over 10 amps and then nothing, the led stops working. Also direct driving them with high quality cells like my Samsung 2600 mah cells will draw upwards of 5-6 amps, too high for continuous use. I have a couple direct drive lights and I have to use cheapy Trustfire cells to bring the current to around 4 amps.
These sound like a prime candidate for running on A123 batteries. I tried them on an xp-g linger special from nailbender, but ended up buying IMR's instead. On high the A123's were as bright as the IMR's on med. If these have decent output on the LiFePo4's, I may be able to narrow down my battery stock to only two types, and more specifically, two sizes.