Peggi sent me! I got mine from Speedpress
http://www.speedpress.com/products/2/2, which is a company that makes mats for photographers and mat framers. I called them and they said they sell lots of them to quilters.
Bought it in 2011, and it's still holding up beautifully after many, many cuts. They have quite a few different sizes, and can custom-size a mat to your specifications. Mine is 38.7 x 71.7, the largest non-custom size they sell.
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I will say the one caveat is that their corners don't start at -0-, which can throw some people off. It's not been a problem for me, but it's something to consider. If you custom order a size, maybe they can change the numbering so it starts at zero. Never thought about that. Regardless, it definitely won't stop me from buying it again when this one has to be replaced. It's held up much better than any other mat I've purchased.
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