My kids were watching The Flight of Dragons today, a fine old Rankin Bass cartoon. The villain in the movie is an evil wizard named Ommadon, voiced by none other than James Earl Jones. While an enjoyable baddy, his character is obviously quite different from Vader. I imagine a number of lines could be used from the cartoon to voice Vader in your edit to quite comedic effect. Listen to some of his lines and delivery and I bet you could find places to sneak them into your edit.

http://youtu.be/Uw9bny88OuY