It's a funny thing: Jewelry that pays homage to technology can work just fine, but it seems to make less sense when it actually functions. Why, for example, would one need to carry a computer peripheral around one's neck?
Case in point: The oval-shaped video MP3 player from X-Micro, which is designed to be worn as a pendant. As Chip Chick rightly points out, watching videos chained to the neck doesn't seem like an optimum viewing experience, especially on a screen that's so small. Nor does it look quite like anything under glass at Tiffany's.
But if you insist on wearing a working gadget, we suggest something along the lines of the "Kodak 1881" locket. At least cameras, once upon a time, were worn around the neck for a reason.