Absolutely excellent post! This is also why keyword researchers are not always accurate -- some keywords have traffic surges, and then the traffic slowly dies off.
While this sounds fairly high maintenance, it also sounds like Google'd love you for it (the whole adding new content regularly thing). If you managed to pick a keyword that wasn't quite as attractive as you thought it would have been, I suppose your earnings would suffer (new things are not popular for very large periods of time).
Something pretty spectacular would have to be posted, if someone else wanted my vote for http://www.netbuilders.org/net-build...ntest-767.html (Will's translate post would have come close, but I don't believe he's participating... not so sure, he said that the "moderators" were not participating).