I've got a Smart Lunar 35 Lux LED bicycle light.
It's obsolete now, I think, but it's fully waterproof, uses two AA batteries (last over a year), has two constant brightness settings (and the stupid flashing one), and has become my general pocket torch as it's so small and convenient. I put electrical tape round the seal, as it once came open when I dropped it, but it gets used for all sorts of stuff, such as DIY, and even checking for lost nuts and bolts on the floor (hold it horizontal at floor level and scan like a lighthouse).
There are a lot of LED bike lamps and many are really good. They have to be waterproof and pretty robust, so worth a look, I'd say.
E.
PS: I used to do a lot of caving, & have a lot of Petzl kit. They weren't my first choice for lighting, as other (British!) brands were better, but those have largely fallen by the wayside now, whereas Petzl lighting has flourished, so they can't be all bad. Worth a look if you have the funds, but also look for other LED caving lamps - none will be cheap because of build quaity and light output, but they have to work in one of the worst environments possible. Also see Oldham & Ceag mining headlamp LED conversions (The Oldham headpiece is THE classic underground, fully waterproof lamp, and still my favourite, although the original lead acid batteries, now obsolete, were heavy and horrible).
PPS: Caving lamps usually have at least two modes: Lighthouse-type beam and wide angle. The bike lamp is a good compromise, still a bit narrow, but wider than an old-fashioned torch with a reflector.