I have a special-purpose plugin (UniqueVisitors) I wrote a couple years back to help me track an individual human user that was using dynamic IP addresses.
It’s sole function is to add an image to the footer with a unique ID, like /wp-content/plugins/unique-visitors/spacer.gif?ffbb904f3eaca4c1acc
Detailed analysis, not exactly, but I then use AWstats (and other similar tools) to analyze my raw web server logs to track this particular visitor.