I think he's asking something a little different from the three options you were suggesting, Mark -- he's not asking to make the image anamorphic. He's already cropping the image (16:9 letterbox matte), and now he wants a QuickTime movie without the black bars top and bottom.
My guess would be to create a new timeline whose frame-size dimensions are 16:9. Let's see...if your original picture was 720x480, then you'll need to make your new timeline 720x405, I believe. You're trying to maintain your horizontal pixel count while shrinking the vertical, so if you have a different frame size to begin with, you should use (Horizontal Size/16) x 9.
Use the same codec settings, frame rates etc. The new timeline should be able to crop out the unnecessary parts of the picture and your resulting movie file should be 16:9 in aspect ratio but without the black bars. Can't go to tape with that, though.
This isn't a process I ever do, so if anybody has a dissenting opinion to offer, I'd be happy to stand corrected.