Scanned with 123D Catch from an original sculpture by R.Shipman. This is not a remix of my earlier "White Rabbit" release (http://www.thingiverse.com/thing:480846), but uses the same scan data.
March 21 update: I've posted a "keyed" version that makes it much easier to line up the top and bottom halves. The older version has been removed.
The mould (or "mold" if you're reading this in the USA) was produced using the Boolean, Plane cut and repair functions of Microsoft 3D Builder, which produced a much better result than I was able to derive from other tools I tried, such as MeshMixer or Netfabb.
I do not recommend reusing moulds used for food products, due to the risk of bacterial contamination. This should make a pretty great silicone mould, though.