Word in our inbox that music publicity firms Magnum PR and the MuseBox have merged, combining two pretty big rosters. Magnum reps the Radio Dept., who are great, and Savoir Adore, who were wonderful at the Seaport over the summer. The MuseBox has been making some noise with the The Dø, who played a couple shows in New York.
I actually did my first internship way back in the summer of '07 at the MuseBox, back when they were sharing office space with Spin, and they've got some nice folks there.
It's pretty uncommon, at least in my experience, to see mergers between firms - it's definitely not uncommon to see individual publicists switch places, but less common to see full companies come together. (The new, combined company will continue to use the MuseBox title.)
I know publicists sometimes get bad raps, but our lives as reporters (or just bloggers) are definitely better off with them. Best of luck to the new venture!