I recently published about my experiences of using Emacs for Ontology building (http://www.russet.org.uk/blog/2161). A fairly niche subject area, but I was did get a couple of responses asking for my code; curiously, it appears that although I started to write this 6 or 7 years ago, even before this working draft was produced, I forgot to ever release it publically. The code is now available on my website.
I have also taken the opportunity to move my versioning to Mercurial for all of my Emacs packages — originally I used Subversion. This is fine, but the servers tend to get deleted over time for projects that are rarely updated. With a DVS, I keep the entire project history on my local machine which is a considerable advantage. This is also available from Google code.
omn-mode is a work in progress. At the moment, I use it to edit with Protege as a visualiser, but it could really do with some additional command line support; for checking syntax in particular, which would allow Emacs to jump to the relevant line; reading Java stack traces, followed by M-x goto-line is all very last century.