I was going to do it when I had my ZX sled, but like was said, it just doesn't look right. I ended up finding a stock seat that had been raised about 2 inches with foam and sewed-in cover material. It looked nice and worked well.
Although in retrospect, it hurt mountain riding, as it was harder to move around on and it reduced the amount of lean I could get with both feet on the boards, as it kept my outer leg in check more than a stocker.