Perhaps you could create them in a 654x480 still image in any photo editing/painting program, set the background to transparent (save as GIF maybe?) and then load this file into the overlay track. You could then use the Begin/End controls in Pan/Crop to slide this into position. Add the score as a text event on the top track.
Thanks for your reply - I used Paint Shop Pro 7 to create the image, but it is pretty basic - I would like to see what you came up with but could not open the link, even when I copied it into my browser - any suggestions?
Sorry about that. Shortly after i posted that link my web server crashed and burned. I've got a temporary spare server running now so you should be able to open the link.