Nice... but I can't get past the fact that ice burgs float about 90% under water. What you see above water (the tip of the ice burg) is just that, the tip. Ice is just frozen water.. the only reason it floats is because water expands when it freezes.
Glad to see this in game! ...could you make it flex back and forth a bit? I believe they tend to do that, especially the carbon nanotube variety. I bet you could also make an orbiting elevator as well, such as the ones used in the Red (green, blue) Mars series of books, using offset rendering :)
In the first picture, there is a tiny mis-alignment visible running vertically through the first windows to the left of the front door. It can also be seen in the white part of the roof directly above the windows...
anyway, it looks awesome otherwise!