Create Moderation System in Wordpress for Private Messages on Site

With the new messaging system in place, I now need a way of monitoring the messages as they come in, in the event users are abusing the system and need moderation. Currently, there is no way to see the private messages easily. I would like a simple feed showing message thread titles as they come in, with the ability to click on each on and expand the message thread. This also needs to be searchable, as suggested.