Hey Stephen,
I think if I was really sure that there will be longer times when I will NOT use the machine is realistic (you may change your mind on that, regarding how useful a CNC is and that it works while you do nothing), I would store it on a flippable desing like Jim @JimHatch’s modification of the Fisher-style table concept to accomodate the 48″x32″ Journeyman which can be seen under Lessons Learned for Flip/Fold up/down Tabletop, or like Joshua’s @RockingMallet flippable table variant for the Elite 48″x32″ Journeyman or Lee’s @TDE Fold Down Wall Mounted CNC Table.
In this case, at every machine shutdown before storage, I would drive the X axis to the position it will take with gravity when the machine is powerless and the stepper’s electromagnetic detent is gone, to avoid that it moves after flipping. You may also retrofit stepper motors with brake which will ensure the steppers will never move while powered off, or use Jim’s good ole low-tech method to prevent motors from moving with gravity 
However, even if there exist even flippable table designs with vertical clamping, I have never seen a flippable design with a CNC enclosure. I belong to those who believe an enclossure is necessary, not only because of dust or noise, but first of all because of safety. The debris of a broken bit can harm humans and animals severely. The manufacturer of my spindle, in their spindle manual, makes the use of a CNC enclosure mandatory.
I find this enclosure concept rather mature, see also here and here for its integrated dust outlet. I would make it dust-tight and isolated against noise. What this enclosure takes into account and what I find important, is what @cyberreefguru stated in Cnc Table Hindsight 20/20: