As a very general rule, any item of clothing that costs thousands of dollars new is a good thrift find. And Cucinelli is even better. I had the chance to handle some of his stuff at an outlet recently, and it is really incredible (and sadly way out of my price range even at sale prices).
I'm not sure whether this logic holds up. After all, Armani, Hugo Boss and many others cost a lot of money. You might get respect on here for how much money you're going to get when you flip them, but nobody's going to need a Robert Graham shirt to clean up the mess they've just made.