Derelict Xorn Colony Ship
In my game, the Xorn ( http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/xorn ) were a space-faring race once.
The old colony ships, giant inert husks of steel and rock, still float about, and are sometimes used as stations by other races.
The picture is an illustration from an upcoming short PDF that ties in with my game. It will contain a handful of more unusual ships, as well as a small warship with floorplan for player characters.