Build a ProSites site in a Staging enviroment

Hi,

I would like to be able to build my ProSites site in a Staging environment where each new user who sign up, will be able to build his / her site on hers staging site.

I refer to my post here for more details
https://premium.wpmudev.org/forums/topic/prosites-and-staging-recommended-plugin-or-other-possible-options#post-1033872

Dennis