Okay, so there's no DM widget.
Although, your suggestion did remind me that there was one add-on I was looking over last week that adds this messaging widget that seemed like it functioned like an improved messaging system (it sort of seemed like a chat room). I was going to put up a poll about it to see what everyone else thought of it, but I haven't gotten around to it yet.
Once the designer has finished the new logo, the header space should be a lot smaller after that since the current temp logo is a little off.
I'll try to adjust that now because I completely agree with you that it makes the header kind of off-puttingly large height-wise. It won't help the empty space in-between, though.
I'll update this again once the changes have been applied.