Oh, yeah, didn't think of that. What is most likely going on is a layered shader as Nitro mentions. The top layer is a reflective blinn or whatever with a sampler info connected to a blend color node (facing ratio > blender) which is then connected to the blinn's transparancy. The layer beneath could be the same blinn but with reflectivity turned off. If you make the two colors in the blend color black and white, you'll have the reflective material transparant in the center and opaque on the edges, thus giving you refletivity only on the outer edges.
Duh! Should've thought of that earlier.