Finally had the time and drive to make a staff prop for myself, the way I envision one. No fancy shapes or stuff - just weathered wood, brass, leather strip and a crystal. Something fit for a generic fantasy cosplay/photoshoot/LARP.
The crystal is shaped of Polymorphus covering a tube with a 18650 rechargeable battery, 3 to 12 V converter, LED strip and the staff's raison d'etre - magnetic proximity switch.
By bringing a magnet close to the dark spot you can see on the crystal it's switched on - and bringing a magnet close again switches it off. A elegant, simple, non-power consuming solution for a bit of magic, based on a magnetically loaded reed switch.