Google's Report Spam button is actually pretty close to that. If the message has a List-Unsubscribe header, it offers to use that after hitting the Spam button.
And usually they don't really take 10 days, but that's the limit the law permits so they give themselves as much wiggle room as possible.
Why should I have to do extra work just because MTV is hostile to users? Or because Hallmark's database takes 10 days to update, gamespot's unsubscribe servers are permanently broken, or because some crappy website demands your login info?
http://imgur.com/mzqKk http://imgur.com/Yn5eD http://i.imgur.com/yoky5.jpg