There is a thread already about shaving the stock seat, just google "shaved fz6 seat" that should work. Otherwise there is a euro seat that is lowered, but that is going to be around the price of an aftermarket seat.
Not sure if you have had your seat lowered yet...if not Tony Archer based in Huddersfield is a legend. If you google him he has a website. He recently did mine and i have just got back from Scotland with no ache or pains in my butt (he raised my seat slightly and made it very comfy)