Hmm... I'm now realizing I may have seen one of those Windsors: 6 tuners, like guitar tuners, but only 5 strings put on. That would require a conversion on the nut, wouldn't it.

There's another variation in the pictures toward the bottom of this thread at Banjo Hangout: clicky. The "short" string goes up to the head like on a Windsor, but outside the neck, rather than through a tube.

~ Becky in Tucson