It will be in a D cell maglite, the pot will be an external that protrudes from the neck. The driver does not necessarily have to be round, as long as I can fit it in the neck of the light, and heat sink it if needed.
Sorry couldn’t resist, but seriously do you already have, or have picked out the the external pot yours using so we can see the spec’s?
What input voltage and 3 or 6v out?
Also are you looking for a driver that has provisions for an external pot specifically or are you ok with simply replacing / paralleling the pot to the sense resistors?
I have some from Fasttech that have a 2 Amp diode, the ones from Illumn I got have (SS14) 1 Amp diode. I’ve never tried to run them up to 2 amp.
Here’s the definitive review:
The sense resistor on the AX2002 is the 'R500' right where the black wire attaches.
However... most pots small enough to do what you want are not meant for repeated adjustment, they have a very limited number of turns before the wipers start to wear out. They're really only meant to be used in a 'set it and forget it' kind of way, not like a dimmer. Pots able to withstand continuous use are much bigger than what will fit where you want it to go.
The amount of current through the pot may or may not be another issue, depends if you want to use it to completely replace the sense resistor so it can go from 0-100%, or in parallel with the resistor to give a stock output at the low end of the adjustment, plus whatever is added by the pot adjustment on the high end.
Drivers like the TaskLED stuff can use an external pot for dimming, but they do it in a totally different way. The pot doesn't carry any significant current but instead is used as a sensor input for some chip on the board that reads the pot position and adjusts output to match.