Cropping headers and footers

Ok, as long as it seems like we're all pitching in with suggestions..

I'd love to be able to "crop" a page before applying extraction patterns.

I used to do this a lot when I was writing scrapes by hand in VB. I guess it's like adding another extraction layer in the mix, but a simple example would be this topic post page I'm on right now. (Post a suggestion of your own to see it. Hint hint.) If I wanted the stuff in the middle of the page I'd crop the top up until the "Post a new topic" and then crop it from the "Add a Poll" to the bottom. Then I'd start in on applying patterns to the remainder -- usually the meat of the page without headers and footers.

It was also handy when I had a bunch of sections in the page that were very very similar. It solves the common problem of "how do I scrape two identical but subtly different tables?"

Just a thought. It's really the only thing I miss about coding by hand.