On the video buss master track try adding a Motion Blur envelope, try setting it to a significant number of frames.

Also in Project Properties try different forms of motion blur.

If you have a camera such the the XDCAM EX1/3 you can do this in camera using Frame Acculation. Other cameras can do a similar trick except they might call it Slow Shutter.

Problem with all of the above including your idea of stacking lots of tracks is they are all fake and obviously so and scream Low Rent. They also really give the game away if the camera moves as everything is affected.

You can get an extemely pleasing result with plugins in After Effects but they are not cheap and take serious amounts of render time. If you want to see how good they look, look up Twixter.

Here's my off the wall suggestion.
Try doing this the cheap way but play around with motion. Have your talent move at quarter speed, apply 8 (or more) frames of motion blur and then speed them backup to normal speed. This should avoid the problem of seeing multiple images, try to aim for a fluid trail.

Bob.