bapase is a set of scripts that uses various metrics to detect packages that are good candidates for orphaning or removal. After orphaning or removal is proposed, bapase allows to track the process, so the orphaning/removal can occur after some time.
Original thread on debian-devel@: http://lists.debian.org/debian-qa/2007/10/msg00031.html
The data and the scripts are in the collab-qa SVN repository: http://svn.debian.org/wsvn/collab-qa/bapase/
Live data: http://udd.debian.org/cgi-bin/bapase.cgi