40 years, I can't even imagine the overhead required for such an endeavor.
We have a company in Ontario, Maple Dale, that sells 1, 2, 5, and 10 year cheddar. I've only had the 10 year, and it was pretty powerful stuff.
"William's Cheese" in Northern Michigan regularly sells a "13 year cheddar." They are a pretty giant outfit known for processed cheese products, but do have a few real cheese gems available.