The screw came out easy enough, but below that metal and plastic ring is a circuit board that's loose enough to wiggle but attached to something on the other side, my guess is the wires to the LED. Because the attachment is on the far side, you can't get it at with a solder gun. I'm pretty sure they screwed the circuit board in with that ring, then soldered it from the far side, then glued down the bezel on top.
I haven't heard anything at all from Niteye recently, but I agree that an Eye15 without and the stops (and an updated emitter of course) would be excellent. My EYE10 is still one of my favorites because it doesn't have the stops and thus goes lower than any other light I own.