Part of the problem is that you want your word/phrase to be a zinger. I'm afraid that's incompatible with the concept of the altruistic-probono-professional, one of whose attributes is a touch of self-effacement. (Otherwise I'm not doing this for the general welfare but rather so that You [whoever and however-many You may be] will think I'm pretty hot stuff. And so noble, too.) That makes "zingerhood" a bit oxymoronic. Pizzazz just isn't part of the description.