If you like the Low D sound of your baritone ukulele you may enjoy a subscription or occasional newsstand purchase of Acoustic Guitar magazine. I think this February's magazine is sporting a baritone ukulele or vintage small body tenor guitar. Only Mumford & Son's knows for sure.
Notice that there are "5 Songs to Play." This is a regular feature of the magazine. I also notice the "Roots Fingerpicking Basics" and "Pentatonic Patterns."
I also notice that one of my Luthier friends, Tony Graziano, regurlarly advertises his services in the back marketplace section of the magazine. Tony has made some beautiful baritone ukuleles but it is hard to get him away from building long enough to get some photos. Perhaps our bari-friendly, friend Sandor, will get some shots soon?
Here's a Mumford & Son's video sans bari...