I want to do this on my lvl 70 too but it will take some time (days,weeks)
So let's start:
1) Bloodsail: You probably have Bloodsail Admiral so you are atlest friendly with them.I would suggest to go to honored since you dont need to have both The Steamwheedle Cartel and Bloodsail rep at the same time.
2)The Steamwheedle Cartel : Grinding this rep is a little tricky and time consuming (well the whole achi is :S ) so you have couple of way to do it:
a)You can farm the pirates in Ratchet ,Tanaris and STV (the ones in tanaris give 5 rep with Gadgetzan and 3 with others,Ratchet ones 5 with Ratchet and 3 with others ,etc.)
b)You can do the quest http://www.wowhead.com/quest=9259 and get 500 rep with BB,Gadgetzan,Everlook and Ratchet but you lose 500 rep with Bloodsail ( this still works in Cata)
c) You can farm keys from Dire Maul north ( i m not sure if this still works)http://www.youtube.com/watch?v=TxEHrallTnM
3)Darkmoon Faire:The easiest way to do this is to make 1480 rogues decks (http://www.wowhead.com/spell=48247).Check price on AH ,and also look for cheap high lvl decks.The rogues decks gives 25rep each.You need to turn in 160 Rugged Armor Kits until 2000/6000 Friendly then 1480 rogues deck til exalted.
4)Ravenholdt :Farm yourself til 11999 honored then get your rogue and farm (pickpocket) boxes from mobs.
So that's it a quick guide hope it was helpful.
PS.:Sorry for some typo mistakes but i was writing while i waited to log on to server.
Good luck farming it!