These things would go really well with the realistic darkness mod.
Actually a good request, and I think it'd be doable (given that we already have a mod with mining helmets that shed light), although it'd probably be hard to use without mods such as "pick up and haul" (to be able to tell pawns to pick something to their inventory) or "simple sidearms" (if the lantern/torch/flashlight would occupy a weapon slot).
Yeah, sidearms actually made me think of it.