Just wanted to update that I haven't forgotten about this. I've been a bit busy with school lately so I don't have that much time to do anything fun for long periods. When I get around to finishing this, I'll probably post it in the script database.
By the way, tested out using blank rectangles and I saw no lag. Now it's just a matter of figuring out how I should go about doing it, like keep it the same shape or randomize it every X frames. Any ideas?