When commissioned and +50 relations (or +80 w/o commission) with a given faction, that faction allows the player to use their facilities to build ships, weapons and fighters (up to 15% of their production capacity) using blueprints known to the player and that faction.
This allows the player to
1: Bypass commission restrictions on ships and weapons produced and sold by the faction.
2: Bypass lack of available inventory in markets
3: Use custom production regardless of whether player has own colony; an alternative to raiding and/or exploration for blueprints to gain recurrent access to such equipment. Good for players who wish to remain small fry, commissioned with a faction.
The price could be hiked (accounting for materials, compensation for occupied production capacity), and use of this would require the player to own storage of some kind.
The only proverbial spanner I can think of is the UI/internal game logic; Determining which faction(s) whose facilities you're using etc.
