A few years back, I covered an old Fizik Nisene saddle with some of the lower leg part of my old Levi's jeans (the part below the knee with less wear). I think I just used normal contact glue, and it held up nicely. I did not take the old cover off, so it was pretty easy to get to work on.
The Nisene saddle has the screwed on "scuff guards" on the corners, and under the nose, which makes it easy to fold the cloth or leather under and finishes it off nicely.
The jeans cloth was acually surprisingly easy to keep clean. Just let the mud dry, and slap it a few times. Simply dust it off! And you will have a nice "no-slip" cover on your seat (if you like that).
It worker for me, and I will do it again, as I have another old Nisene on my hack bike.
Specialized Stumpjumper Cro-Mo '97
Vicini Columbus Cromo 1987 road frame (project)
LaPierre Zesty 714 '09