Haha...you are right. Someone did tell me to tape 3 x UF-2100s together to get a triple XM-L. The UF-2100 is $14.50 cheapest from what i come across though, i like that thing with 4.7kHz PWM!
But this really is a floodlight. The truth is this.... Something is preventing it to be so far below SR92's 45k cd, coz even by sheer power as a floodlight, it should be able to do above 45k cd. Heck I got nearly 30k cd from the 54mm diameter Sky Ray 3800, DDed of course.
I guess the spacing is a bit worse than typical budgetlights. Take the above mentioned TR-J12 for example, it's 44k cd for 9 XM-Ls. Area is 30cm^2 for TR-J12. Minusing off those area which are unused and it could be say 25cm^2? It's actually about 460 lumens for each XM-L, it's not a flashlight which has its emitter gunned like there is no tomorrow. Eg, DRY.
Feilong is 8cm, or 50cm^2. And it has a whole single reflector. But it is noticeably less throwy than 45k cd.
What I can think of is :
(1) Noticeably less lumens per emitter than even a TR-J12, low drive levels. Could be due to (a) driver unable to support those power, though they are "rated" - doesn't mean that they need to do that in reality (b) battery cannot supply such juice. But not likely as you need only 10 amps for each 32650. I have good experience with the 26650 and 32600, the 32600 happily does 4.5A and does not even get hot much and lose much capacity.
(1a) what I am afraid is that due to point 1, the lumens output is there also. That is logical.
(2) Heat is affecting the output even at lowered drive levels due to the emitters designed in a cluster.
I actually have the XTAR S1 which is effectively a 85mm head diameter light and 3P battery config, and i have examined the driver space. Not too much space there, but of course much better than the usual multi-XML lights that i have (quite a lot there). The TK70 is a 105mm class multi-XML light that accepts the same 32mm diameter cells, slightly better. The thing is that heat output of the lights affects them driver electronics. You can drive them hard of course, but they won't last past a few minutes. That said, the DRY 3 x XM-L is a different breed, it's a light for the lumen junkies, truly unlimited/unrestricted stuff.