You might want to check these out:
http://www.brookstone.com/shop/thumbnail.asp?world_code...o%20Accessories*Seat
I use the one on page 2 that costs $30.
I use it for my cloth seats H3 and I love it. I bought it so I could sit higher in the seat (since they didn't build cloth w/power adjustments for some stupid reason!) but it is very comfortable (and I have a bad disc in my lower back). I drove 17 hours straight from ATL to Minneapolis and was never uncomfortable.
GreenH3