Have you considered an Alto's Quilt Cut? Mine is 20" X 29" and holds a standard 18" X 24" cutting mat. The difference is that the cutting mat sits on a board that has sliding clamps along the 24" side. This holds fabric coming off a bolt securely in place while working with the portion laying on the mat. The rest of the yardage can hang off the side on a chair or another surface. I don't care for the attached ruler though, so I remove it and use a 6" X 24" ruler for better accuracy.