This may be a repost, but I searched and didn't see anything. I'm sure you all have heard of the Airhawk by Roho. Well, I am using a Freedom Air cushion by Star Cushion.
I am a medical equipment distribution manager for a pharmacy wholesaler and thought you'd find this ineteresting.
Roho and Star Cushion started off making (and still do) medical air cushions for wheelchair bound folks. They're very comfortable and are designed to minimize sores and skin breakdown for their users.
Both started applying what they'd learned in the medical industry to motorcycle seat cushions.
I've got the Freedom Air for my bike and my brother has one for his BMW 1200LT.
These things are great! Really extends saddle time and comfort. If you are looking for a relatively inexpensive solution to the $$ needed for a replacement seat, you may want to give it a try.
The other added benefit is that I take the cushion and use it as a stadium seat, picnic table seat, etc..
Here are a few links if you're interested. I guess this would be considered an endorsement, but it's not REALLY. I'm not getting paid or anything,, just thought I'd pass along my thoughts.
http://www.longeride.com/ http://www.therohostore.com/Departments/Comfort-Products/AIRHAWK-Motorcycle-Seat-Cushions.aspx http://www.mcnews.com/mcn/model_eval/2011JuneBmprs.pdf 
