Dear Peter:
I have seen that unit on display at the Montreal Musee des Ondes Emile Berliner. They also used to have another one 'on reserve'. I have visited that museum frequently with my class [ History of Electroacoustic Music], which I thaught at McGill until recently. I do not know if they will 'part' with the extra unit.
Just Google <Musee des Ondes Emile Berliner> and you will get into their site.
Good luck, alcides
PS: I am know for putting Emile Berliner ABOVE Edison as for sound recording.... Berliner used to have his factory in Montreal, from ca. 1895 until WWII.