This is fairly simple. Create a kingle top level folder for all the power user groups e.g. team_share. Then create a folder for each group or team that has power users. These folders will be secured against a specific team Application Role.
Power users will then be able to save their work in the team folders they are members of.
They can save dashboards in any sub folder then publish these via links on a central or team landing page.
You need to set the correct privileges for changing permissions and lock down other privs to the central it project team.
Adrian