There is a Top Box Back Rest Pad for $30.
"Description: Pad for the Top-Box. Give your passenger additional comfort and support."
Of course you have to run the top box to use it. I added one of these pads when I picked up my bike, but the passenger would have to be sitting pretty up right to use it. My girlfriend is usually leaned over at the same angle I am, so it doesn't get used.
[ This message was edited by: dart330 on 2007-07-04 15:08 ]