Since others have posted odd banjo sightings (even Wallace- he's Plasticene for goodness sake!), here's my two penn'orth.
I've just come back from a week in Somerset, and in the excellent Rural Life Museum in the Glastonbury Abbey Tithe barn, near photos of village bands is a big drum from the Ilminster Village Band, a keyed bugle and a banjo. The banjo has a short neck like a tenor, but six pegs on the head like a guitar-banjo and one on the neck like a 5-string banjo. The neck is nicely finished and though the pot is fairly plain it looks a professional make, not a home made one.
I know there are lots of varieties of banjo but this is the first 7-string I've seen.

RtS