Does anyone know how to do this (a sequence shot) in video? I've searched the internet but haven't found a tutorial on it.

http://www.dgrin.com/attachment.php?attachmentid=14783&stc=1&d=1157570281

Just shoot the entire thing in one go and then layer it in a compositing software. Mask out the portions that you don't want. Since the background is constant it should look pretty good. Half an hour's job.

BTW, It's important that the camera be locked down if you want to do this.