A large buoyant structure in the calm upper atmosphere envelloping the Earth like a nest of orbital rings may be interesting. Because balloons are nonrigid and mobile It would need active position and orientation stabilization at each hub and general drift countersaction for good communication routing. The nonrigidity may even simplify the stationkeeping by reducing the compounding of errors. It would improve pay-as-you-go.once started.
I've been fumbling my posting attempts so I'll post here.