I can't quite point you to any direct site that sells something like that but perhaps you can make one yourself. I made one and so did this girl:
http://eileengalvin.deviantart.com/a...757216&qo=7 6
by using a small (mine was plastic) christmas globe and painting it (I dipped mine in water + paint in a bowl for all-around coverage) then cut it along the middle before putting crafting mold for the latch and then further detailing it with paint.
Or you can just buy the crafting mold (in a professional art store) and try to mold it as the entire necklace and paint it (as a solid ball but it won't open).
If not, antique stores usually have some strange necklaces like these that you can try to find.
Haha I find it ironic how the bell is giving you "death glares" (or the alternate name "evil eye") because in some traditions, red ribbons and bells are supposed to ward off things like that.