We're excited to hear that you love your new shirt! While we can't narrow down the search to that specific blend of fabric, the rei.com website will allow you to filter down to hemp/linen/blend that will give you a group of options that you can check out. Feel free to look at those fabric blends here. Based on what we could see, it looks like Patagonia uses that specific 55/45 hemp/cotton blend for a couple of their shirts, like the Patagonia Trail Harbor Tank Top and the Patagonia Trail Harbor T-Shirt.
Hopefully this helps!
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