I did find a hat in the last dungeon on the third level but it was an ordinary hat and not the Sage's hat.
Something strange did happen recently though. While in ACTIII, I had several items at the battlefield that were not identifed and I could not increase that skill anymore than where it was already at. But for some strange reason, I arrived at the battlefield and opened my chest and all items began to identify rather quickly but turned out to be ordinary items. Some items that were already identified lost all their attributes and added skills. I tried reloading the game and investigate why this would happen but could not find a cause and could not prevent it from happening again. I'm assuming this is what happened to the Hat???