Most caving oriented lamps fulfil a lot of these criteria, perhaps not the specific LEDs you want.
There was a thread on the other flashlight forum a long time ago where a user had modified an 18650 Zebralight to use a remote cell- he’d drilled the tailcap and added a cable gland, then made a “dummy” 18650 cell out of wood/plastic to hold the wires against the battery terminals. External cell was plasti-dipped if I remember correctly.
I’ve plans to do a similar mod with an Emisar DW4 and the 18350 tube, just need to find the time/connectors.