Well I'm not really having any luck with Flash CS4. It keeps crashing on me whenever I try to add the overlay which is infuriating.
I personally am starting to dislike this idea, possibly cause I'm sick of looking at it, or possibly cause I'm insane with fury over Flash crashing so much. I'm probably going to start a new idea and call this a test.
Click here to view it. There are arrows at the sides of the page which help you navigate along the background.
Here's the overlay I was going to put on it. On Flash it's got a blurry filter on it and it's really dark: