Well, the only way I could see the rain shot working would be this:
You'd have to find a rain element shot against a black screen...most likely from a behind-the-scenes on a DVD. Could be a pain to find one.
I also found this website: http://www.vce.com/ImageLibrary/wrs.html
If you could get larger resolution of a few of these, it just might work! Looks like you'd have to buy it from their store...hmmm
It'd probably be easier to create the element in Motion and comp it in using Final Cut or Shake.