kikkoman
(kikkoman)
2
Driver-wise? Should be no problem. The thing is huge inside.
16mm ID, with one side flat - but you can grind or file that away, so you could even fit a 15mm driver flat on the original spring PCB.
16.5mm deep, so you could fit it in vertically.
The thing is so large you can chop a good chunk off the head and still have enough room for everything:

You’ll need a matching pill of course to fill that space up, and I’m not sure if the 20 mm optics + triple MCPCB fit without a bit of file work. I think they just might.
For 2x14500 though you’d need a buck driver… or 6V LEDs. Triple XHP35? haha