I don’t mean to sound like a dick here at all man but for me to do a project it has to be something I’m interested in and a 6v LED in this light isn’t currently something that appeals to me (heck I couldn’t rip the XHP50.2 out fast enough!)
Since it is able to be locked out at the tail you always have the option to do a zener mod and run 2x26350 to a 6v led that way but what if anything is there to gain over stock? Not runtime going down to 2x26350’s… Note you’ll also loose lvp as there’s no voltage divider on board (voltage is monitored internally by the MCU and thus batt monitoring won’t function at all).
I am more than happy to share the actual eagle files if you or someone you know uses eagle, there’s enough open board space to add whatever you’d like on the switch board.
If there was a Nichia 144 MCPCB available >20mm I would definitely be much more open to the idea to alter it with a LDO then but using a 20mm mcpcb in this light looks like a nightmare (you already have to be attentive to solder joint size to keep the reflector from shorting with a 26mm MCPCB).
Sorry. You could always order my boards, leave them bare and piggyback a Lexel LDO driver onto it!