The reflections skybox looks decent enough, actually. It can be enabled by adding a single line to the renderer, but it needs a recompile to work. Like they mention in that link, there's a small issue around the edges of the map, though it's not the end of the world (pun, haha).
Now committed: I really believe that I should start doing some metal mines... But, I really don't know how would they look like... Hmm... Does anybody knows good reference images?