Elan Cutting Mat 36x72 Black & Taupe, Extra Large Self Healing Cutting Mat 36 x 72 Inch, 5-Ply Craft Board Black, Hobby Board for Sewing and Quilting

72" options seem readily available but I'll bet with a little searching you could find even bigger. I've bought larger than I needed and cut down in the past as well to get a perfect fit.