Not sure may be someone already has one... But I really want to share after my experience yesterday.
Anyway, my trainer sells them, so she suggested me to try one on my paint during a lesson (used one). My neighbor owns one as well for over a year, and very happy with it, so I decided to give it a try. My saddle fits her pretty good, but slips a little on the cheaper one I have. So... I tried it and it stayed so much better, that I ordered one yesterday. And it's SO nice on touch that I didn't expect it at all from "no-slip" pads (at least from my previous experience).
They are not that cheap (although I've seen more expensive in Dover), and comes in 5 colors (Navy Blue, Royal Blue, Red, Black, and White).
Ecogold - Equestrian Textile Engineering (it's a jumping one I used, they also have dressage)
P.S. I've seen my trainer's "order book" and looks like she sells lots of those. :)