For 21700 , there is the L21A version with XHP35
I don’t know if it has temperature stepdown, otherwise removing the NTC on the driver will disable it.
Removing temperature stepdown wont solve the problem, cos then you cant hold it in your hand 
So tldr:
2x21700 big flashlight with good cooling and over 2000lumens
Size and weight isnt problem
2400LM,
no adpater for 21700 battery
So 2x 26650 version can also work on 2x 21700 without adapters?
Is it able to be cold enought to hold even on full 2400lm mode?
If yes I am going to order one right now
abgx1, why 21700? The Golisi 26650 almost matches a 30T and has 50% more capacity.
You will need to make a tube to prevent battery rattle if you go with 21700’s, roll up thin cardboard or something…
Its working with 21700 great, its not even rattling, as they are very long, so there is enought pressure from springs that they wont move
Any plans for releasing a xhp50.2 3v single cell version of this light?
I would see also a New L2 with Larger driver bay
temperature after running for 30mins on full in room temperature without moving
Just a shout out to Simon for good CS. I placed a small order for TIR lenses and asked for a C8 driver retaining ring. He threw in 2 free ones and got the order to me door to door in 2 weeks. Great service.