Replacement chinrest will fit in the cap of your wiplstix case or can be used as a PFD for a very small pet. See DYI page for how to make your own.
wipLstix are very handy travel violins invented and made by me in my shop in the southern Appalachians. The length between its bridge and nut is that of a standard violin, but the body has been minimized to maximize portability. wipLstix is a self contained unit, complete with its 1/8th size bow and inflatable chinrest, all fitting inside a 2" diameter by 24" long watertight traveling tube! The case will also nicely accommodate the chunk of round rosin of your choice.