Just a little heads up... in case anyone else is interested.
I have tweaked version of the Tycho stuff in house which adds some extension mechanisms so that you can make your own packaging types and life-cycles leveraging the Tycho stuff. I originally did a 'fork' last summer, but I have just finished merging it with the latest Tycho stuff.
The reason for this work was enable us to use Tycho for building Tigerstripe (http://www.eclipse.org/tigerstripe/) developed models. We use it to generate binary versions of the models (for distribution with an Eclipse SDK we have) and also to run Eclipse headless to generate artifacts from the models (POJOS, Hibernate mappings etc).
At some point I would like to contribute this work back to the Tycho community, however the powers that be don't like Sonatype contribution agreement.. So I think it will have to wait until the code is transferred to Eclipse (they are happy with the Eclipse agreement).
At that point I am also planning to contribute the Tigerstripe Tyco plugins to the Eclipse Tigerstripe project.