I learned something after buying a new seat for my FZ1. Its not a matter of how soft a seat is, its how well its shaped. My Corbin seat is rock hard but I can ride twice as far as the softer stock seat.
Check out http://www.americanasoftseats.com They have a special going on for the next 2 weeks. They have quite a good reputation for quality and service. Jerry (the owner) will respond to your email the same day.