While cleaning up some badly-sourced articles on Wikipedia, I ran across the one on reverse perspective, a strange drawing style in which nearby objects are shown as small and far-away objects are shown as big. Despite the strangeness, it's mathematically consistent: it's what you get when you put objects between the perspective point (your eye in conventional perspective) and the viewing plane (a window through which you're looking at the world). Here's a nice example:
Although it's been used a lot in art (sometimes deliberately, for effect, sometimes naively, and sometimes for reasons lost to history and hotly debated), I don't know of any attempts to use it for visualization. It has some effects that might be useful, notably the ability to see more sides of an object at once than is possible in a conventional view.