A example of what I am looking for is the windows 7 aeroglass curtains theme by UK58, or Cirrus,
There's a good chance they built them into the shadow images.
Make a copy of one of them, then look at the shadow images and settings, including on the "Advanced" tab. I say to make a copy first because it's very easy to accidentally overwrite the custom shadow images and lose the settings, depending on how their image files were named.
