Yes, I have heard of them. They are supposedly a Chinese/American Hybrid. You can buy a tiny one for $30 at the link below:
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I have an Eaton River Chestnut that is supposed to be a Japanese/Chinese/American cross. It's getting to be a big tree and is making nuts, but the quantity of nuts has been disappointing so far. I hope that it just needs more time, but it is already like 30 feet tall. A Chinese tree that tall will be making 4 times the nuts of the Eaton River.