Judging by how freelancer's tractor beam is capable of exerting a one-directional pull on something almost a kilometer away, I'd say it's a simple thing to scale that up for size and scale it down for power for constant use - without forcing people on two vertically adjacent decks to share a floor.
Also, given the weapons of Freelancer - anti matter, neutron, plasma, tachyon - it's strongly implied that Sirians have highly advanced technology for manipulating magnetic fields - and the neutron guns can be used to create high density structures that can exert their own micro gravities (though this would be highly impractical for the obvious reasons.
