There are a number of banjos described as "travel banjos" available from Saga, Goldtone, and a newly developed one by the Farris Travel Banjo Co. called a "tranjo." Here's a link to his Tranjo 8.1: click here for info and PIX
They certainly are innovative, with a fold-up neck, full fingerboard, and constructed in either maple or walnut (non-rain forest woods).
I'm thinking that this might be just the thing for those of us doing international touring, who worry about losing track of our vintage banjos (lost or mislaid in transit) or having them challenged by customs staff.
These banjos would seem more appropriate for accompaniment of vocals rather than for instrumental sessions. The 8.1 model is pricy at about $900; however, there are less expensive travel models produced or licensed for production by Farris.
I've initiated a thread about these banjos on Banjo Hangout and gotten some useful feedback. Does anyone here have any direct experience or comments?