I've made some progress with Rhizome Navigation, see the sample screenshot below. With GraphViz dot I found a way to display the navigation interface as intended: In this example single pages from this Wiki are represented as nodes. The egdes are generated from tracking data, which means that they do not represent actual links, however, they visualize user behavior: The more often a link is used, the shorter the edge gets. The size of a node depends on how much time users spent on a certain page.
Now let's make this bastard interactive. You need a browser capable of displaying SVG.
More awesome stuff: