There is no need to be a formal member of the GNU Hurd Savannah group in order to be able to contribute to the system. In fact, if we added every single soul that was interested in the Hurd to the Savannah group it'd probably have exploded by now. We have the policy of adding people as soon as they are beginning to make substantial contributions. Simply use the mailing lists for sending your contributions, for asking questions, and so on.
List of members
The list of members can be seen at http://savannah.gnu.org/project/memberlist.php?group=hurd.