At the Centre for Literary and Linguistic Computing (sounds like the title of a journal 🙂 they have mounted a web accessible apparatus to do computational-stylistics exploration. See PCA Online Introduction | CLLC where you can launch an applet that will work with Shakespeare texts.
This is a good example of sophisticated tools available online. What they need is a model that allows us to use with our own texts. I am also not sure about the step by step interface where you go march through pages of decisions. (There is probably no easy way to make it direct manipulation.)