Depends on what you mean by pirate hats.
Bloodsail Admiral's Hat - From having rep with a faction that entails ticking off the Goblins to get
Admiral's Hat - Crafted, nifty, but probably not what you're looking for
Savory Deviate Delight - Not a hat, but can turn you into a pirate for a period of time(good for disguising taurens when trying to sneak into an Alliance city)