Ancient and no doubt discontinued, but I still got some Taskforce 2×AA lights with internal ribs so the body looks as if it could accommodate C cells. Rubberised all over, nice and protecty. Swapped the hotwire bulb for a Maglite LED “bulb”, tossing the end-cap and shaving the hole with an Xacto knife for a snug press-fit.
Nice and hefty, sizewise. Grippy with the rubber. Still uses AA alkaleaks, yet has about 4× the runtime because of the LED.
Might find something similar that’d be moddable like that.