Alright, we all know about the Bloodsail Pirate's pimp outfit, but few of you are willing to give up your Goblin reputation to become a pirate. Well now I have a solution. (I apologize if it's been posted, I posted this on thottbot several months back, but it was deleted within about a week.)
First, find someone willing to lose the Booty Bay reputation. (Or just someone who already has the outfit.) Then group with them. If they kill the guards while you're grouped with them, you will gain the Bloodsail reputation as a group bonus, but you won't lose any Booty Bay faction because you never attacked the guards yourself. (A side-effect of the Argent Dawn fix at the 1.11 patch)
You can heal, buff, whatever to the person farming the guards, so long as you never directly attack the guards yourself.
If you're the person who's farming the guards, you can actually make a tidy sum of money by selling your guard farming services. Made 200g from someone who I let go afk and follow while I farmed the guards. He got his outfit, did the hat quest himself, and I got 200g. (Just be careful where you advertise the service, don't really want this getting fixed
)