There is a skill-mode to be found at ftp://ftp.informatik.uni-stuttgart.de/pub/skill/. The author is Jonas Järneström. Unfortunately, that tarfile consists mainly of byte-compiled files for xemacs19.13 and gnuemacs19.28 - the sources seem to be lost. Someone at Cadence is said to have patched the byte-compiled files to work with newer emacsen.
In Message-ID: <email@example.com>, “JoRobins?” <wulf_homme at hotmail spot com> writes that he started on a new skill-mode. (http://groups.google.com/group/comp.cad.cadence/msg/a69337ab24eb0fd6?hl=en)
In http://www.cdnusers.org/Forums/tabid/52/forumid/62/postid/5473/view/topic/Default.aspx, there is a third one (get the zip file, the gz version does not work).