I'm all for things that make the game better, but this would be a waste of a programmers time that could be better spent building a new skybox for an example.
A 20km sphere would need to rotate fairly slowly. At least slower than the clouds in the current skybox. I'm not sure how the mechanism could be got to work though a constantly moving turntable like object at 0.2rpm just sprung to mind, lol.
If you don't like subscriptions and extra perks as provided by N3V, don't go and buy a new VW Golf. You need a subscription to enable an extra 20kwh performance. Also, forget buying an HP printer as they want you to subscribe to an ink replacement service just to be able to keep printing.