theGhost
As I think about this...

Why don't we create something like Dolphin Site Fronts which could feed off a central DB? Like CraigsList or even CubeCart?

We could multiply your 'macro' Network Site concept while introducing 'micro' versions.

Unity as an Example:
Unity - USA / Unity - UK / Unity - China
Then they JoinForm is universal to the Network while the entrance/community is customized by location?
 
 
Below is the legacy version of the Boonex site, maintained for Dolphin.Pro 7.x support.
The new Dolphin solution is powered by UNA Community Management System.
PET:0.069974899291992