My favorite cinch is the Professionals Choice SMx VenTech cinch (which does come in a 26" that you were looking for).
I believe it also comes in a barrel style and a roper style, if you don't want straight. I have the barrel style.
I've never had it rub a horse yet, and it is very easy to keep clean. I also love the roller on the cinch up side.
Professionals Choice SMx VenTECH Western Cinch