I would want it to be semi hollow in the middle so I could put something in it before brining the two sides together. It would only need to be about 2" in diameter. Any ideas?

Could you use a small ball cake pan, and scoop out the middle while it's still soft, heat the rims to stick it together? Would the silicone cake molds work?
Please let us know how you do this.

I would get a half ball shaped container and chill it. Then pour the slightly cooled candy into it and swirl it around just coating the surface. Keep swirling until it sets up good and then trim the edges. Repeat for the other side and then glue together by heating or sealing with some warmed hard candy.