I had this crazy idea to put threaded rod and tapped holes into a piece of white oak (or whatever) and hang the butt and shafts by their joints.
This prevents any side pressure on the cue at all, which might warp it.
It is important that the threads and rod be sized for a gentle threading (not tight threads) to allow some movement of the cue if something is not perfectly alligned.
Now, place that into a light-proof, humidity and temperature controlled storage area.
Next (crazier step) is to use an atmosphere of Argon gas in the storage compartment to prevent any compoents form oxidizing over time.
If sealed properly, it should be good for 100 years or so with this mega-extreme storage method.