I always envisioned a washer to replace the clear plastic cap in the end of a flashlight
mod. I'm sure you could find the right diameter and they probably have 11/32 hole in the center. The only issue would be, how to mount it in the flashlight? Solder, JB weld? I would love to make one myself, but I've got twins and a 5 year old, so not much time spent doing "what I want" lol