I’ve heard of the kubaton before, but that seems to me to be more of a EDC last resort self-defense thing. I suppose it depends on ones ideal bug-out bag. If you’re looking to maximize potential emergency weapons, the bezel maybe your choice. I also think that a single cell flashlight will likely be too short to serve well as a kubaton. Maybe get a Sipik SK68 and get the mod extension tube as mentioned here.
This is what mine looks like:
Or try this logic: get a 3D LED Maglite with parallel 3xAA shells instead of D cells. Holding the head makes the tail a solid bludgeon. Gives option of running on AA or D, can store 9x AA, which you can steal out for other use or charging, and still use the light since they’re in parallel.
Of course, some people will object to that much weight for a bug-out bag.