That's a great idea if you can do the re-upholstery yourself.
For those of you who are, like me, not adept at this type of thing you can check out the Butt Buffer (that name STILL cracks me up) website -
http://www.buttbuffer.com/info2.asp#2They do the gel pad installation into any kind of seat you may have. It's not as inexpensive as DIY but it costs a hell of a lot less than a Corbin or such seat. I had my Solo Seat & Pilion done this fall and am very happy with the work done. Their turn-around time is quick too.