Optical switch for visible light from multiple endoscopes
Unless your application requires a very specialized (i.e. expensive) CCD, @Dave's answer regarding one camera per fiber and elextrical/software multiplexing is likely the ideal solution.  

Another approach would be to use a faceted panospheric mirror (one facet per endoscope) to allow a single image sensor to view all endoscopes simultaneously without the need for moving parts or shutters, though with attendant distortion and resolution issues.