It <i>is</i> possible to decompress eZ packages using http://www.7-zip.org/ which is licensed under the GNU Lesser General Public License.
I had to decompress a folder selection inside the [Content] (subdir/symlink/file-like-object] of the items : documents (folder), ezcontentclass (folder), package.xml
I guess this means barring any syntax or packaging errors, I should be able to customize the contents of an eZ package and install it into eZ publish as any other package.
I think this is interesting as it allows more experienced developers to simplify how they create their solutions.
Has anyone else used this method to improve their development rate?
Here is an example of a ezcontentclass/class-kbs.xml (the class definition file), it's an interesting read. with a little printed documentation (package syntax / examples) it would be fairly simple to generate an xml class definition for your custom comment class.