The Piccolo banjo can be either seven frets shorter than the Standard, and tuned in "D," or it can be about the same neck length as a Banjo-Ukelele and tuned one octave higher than Standard Banjo (G-C-G-B-D)

Piccolo Banjo: The smallest member of the banjo family. Banjo orchestras popular before the turn of the century used the piccolo banjo as the soprano voice. The scale is short, on the order of sixteen or seventeen inches and the pots are around seven inches or so.

The TAYLOR - LIVERPOOL 5-string banjo has a very ingenious built in capo. It converts the regular banjo into a piccolo banjo, one octave higher. At the 12th fret there is a brass bar with slots for the strings inlayed flush with the fingerboard. There is a separate hook for the fifth string on the 17th fret. The whole shebang is spring loaded with a lever at the back of the neck. When pressed it raises the brass bar to permit the strings to be hooked into the slots. When the spring is released the strings are held in position at the 12th and 17th fret.

Some bits I found lying on the net - might be of interest

Pete