re: did a google search on google (attn: Robert)
I wonder if the earlier button (even when it's visible) is useable by the spider. I don't think it's a link in the normal sense of the word. I think it runs a script to generate the next TOC. Probably only Robert can tell us for sure.
In my search I ran into something which might be worth considering: http://www.google.com/services/customsitesearch.html
They don't list pricing, so I don't know how much it would cost. If it's a reasonable price perhaps Robert could set up a paypal donation for it. Implementing it would be contingent on recieving x amount of dollars etc etc. I'll go on record as being willing to contribute some money for a feature like this.
(Robert feel free to jump in here any time)
-Steve G.