This isn't exactly what I was trying to make. Many times I tried to make a curve, but was obstructed by the limitations of the tools - e.g., can't push/pull through a curve. And I still haven't mastered the Follow Me tool, so there may be possibilities with that which I haven't been able to use. But this is a reasonably vague impression of where I wanted to go. I haven't tried to add texture, windows, or other features, and haven't added color either (initial experiments were discouraging), but the idea is exposed here. I wanted the ring to be a Mobius Loop, but that's somewhat beyond my SU skills at the moment. That little dot you can see in various places is the human sprite for scale.
concept1 by
troubadour1, on Flickr
concept8 by
troubadour1, on Flickr
concept5 by
troubadour1, on Flickr
concept4 by
troubadour1, on Flickr
concept2 by
troubadour1, on Flickr
concept7 by
troubadour1, on Flickr