Ok, just throwing it out there.

Hypercities:
A place were it is practically a planet in the void, but is controlled by the amount of constructors you put on it, it takes 3 constuctors in one place to build the base of the hypercity or the parent bioshpere. Add on constuctors to build factories, labs, defences, trading outposts, defences and offences.

Postives:
+ Can move populations to matian and build the hypercity.
+ Can built industrial sectors and research labs to highten your everything.
+ Starport, home away from home so to speak.
+ Adds new aspects to the tech tree (eg artifial gravity, wieghtless reasearch, solar power etc.)
+ In low planet maps, a real lifesaver.
+ trade is opomised from race to race.
+ puts spin in wars

Negitives:
- Completely erases the need or want for starbases.
- make mantianance cost double or triple (just to make it fair for the planets).
- may make the powerful, more powerful.