[drzax]

I remember seeing this (or something like it) around the time I embarked on my project. Unfortunately, I needed a JS solution.

Another that has be pointed out to me since talking more about my project is http://vis.cs.ucdavis.edu/~tanahashi/storylines/

It's written in Python and looks like it produces really nice output, but I haven't had time to look at it in detail yet.