Well, I'm not sure how well neutral docked things work on ships; I've had factioned turrets fall off an unfactioned ship before after travelling for a while. Though that may only be for turrets and possibly only apply to ships that have travelled at high speed for a while.
Anyway, this has given me the idea that we could probably make some sort of neutral trade or whatever station. I see here two possible implementations:
One, we could make a giant neutral station "frame" with huge docking areas capable of accommodating huge station modules, which would be player ships built to fit the size. A major downside of this is that, due to prohibitions against nested docking, players wouldn't be able to mount turret or dock smaller ships on their substations.
Or two, depending on how proximity of stations to other stations works, and how station cubes are arranged according to galactic planes (if they all snap to the same grid) we could just put a bunch of stations right next to each other. We might still want to have a neutral station in place to provide easy access from station to station and a way to provide gravity while on other faction's stations. The only major downside to this implementation is that I don't really know how well it would work, though seeing how Eric's neutral station fits flush into his planet, I am somewhat hopeful.
Preedit:
Down for the ship is always down regardless of how the gravity block is rotated, however. You could try building them into attached ships, but you can only control their orientation with the orientation of the docking module. It might be enough, though.
Yeah, this was my idea from the start; you would have the docked ships rotated in such a way that it would provide gravity in the direction you wanted.