I have received icons for the "lock/unlock forum" actions.
The "lock" icon may also be used to signal that a forum is in "locked" state. I would not signal "unlocked" as that's the default state.
Please ask Mikael to add the icons to the icon font.
The "lock/unlock" icons did exist already, which is why I can deliver them now. We plan to deliver additional icons for "forum", "thread" and "message", but that will take some time still, since we have to work on other topics currently - do not delay the release because of these. See http://wiki.magnolia-cms.com/display/UX/Visual+design+next+steps.