I've already got an RSS feed from Gentoo Portage for updates available for my architecture, but the list is of all available updates whether I've got the software installed or not.
What I'd like to see is an RSS feed generated from the content output by running 'emerge -pvu --newuse --deep world' (p = pretend, v = verbose, u = update). That RSS feed could be available as either a local file that could be added to any local RSS reader (I'd use Firefox).
That's the idea. Any takers?