(Edit: Sorry, you seem to know all this. Keeping my post here for posterity)

The logical end to this road is continuation-based web servers. See http://docs.racket-lang.org/continue/index.html and my approach to the Arc challenge, https://gist.github.com/1304257

The interesting function which does all the work is:

  (define (start req)
    ;; First, we get input from the user
    ;; Then, we pause for the link
    ;; Finally, we show what the user typed.
    (let ([input (get-input-from-user)])
      (pause-for-link)
      (show-input input)))

Each of these calls - get-input-from-user, pause-for-link, and show-input sends a complete page back to the user and waits for them to click a link or submit a form request. It's a really smooth way of solving some problems.