This would be VERY good and one of the first things I looked for. I'm having an issue that i'm creating a thread for. Detailed roll out options would solve it.
* Animation style
* Roll from title bar or roll with title bar
* Size scale when rolled out e.g. the fence gets enlarged when you are mousing over it.
* Close delay e.g. wait X seconds before rolling up the fence after mouse has left the area.
Another really cool feature is a toggle. Allowing a single fence to show two different sets of icons based on a simple toggle button. Double clicking on the desktop could be assigned to trigger the fences and only certain fences.