glass surface reflection that fades out

I know most of you have seen the common black glass reflection on a lot of websites recently. I’m wanting to do that, but I want the reflection to fade away in the glass, like a gradiated reflection.
http://img381.imageshack.us/img381/2367/reflectionbm5.th.jpg
how would I texture or light the surface so it fades the reflection? I don’t know if there’s a name for this fade out, like degradation or something.

http://www.smick.net/resources/cube_reflection.blend

Unfortunately, I think a reflection that faces out by itself is physically impossible, these websites’ pictures are probably highly stylized. You could do it two ways, though:

  1. You could make a blend material that controls the amount of reflection itself.

  2. You could fake phong with a tiny, noisy bump map to make the reflection blur out and disappear the further aware from the source it gets.