I was working on the Insane achievement recently.
Bloodsail Bucaneers reputation is a tough one now, because Blizzard bumped all the guards at Booty Bay to level 90 and they are hard to kill. So I used phased event mechanics to get to Honored and stopped at that since this is all that's required. This eventually plunged all of the goblins' towns reputations to Hated and given mixed responses out there whether I need all the reputations to be leveled at the same time or not I decided to have them all done simultaneously.
So after that I went to level Everlook, Ratchet, Booty Bay, and Gadgetzan reputation. Goblin factions' reputation is just killing pirates at Ratchet and Tanaris over and over again. I did it when I got bored or didn't have quality Internet connections i.e. airports, coffee shops etc. Pirates drop some cloth that sells nicely, not that I made tons of money, but I looted corpses whenever I felt like it.
I accumulated Darkmoon reputation over time with no significant effort put to it, I got a bit impatient towards the end of it and purchased some cards to make decks, but easily could have done without it by doing dailies and turning in dungeon artifacts.
For Ravenholdt reputation I farmed rogues in Arathi Highlands until it capped at Honored and then started on Heavy Junkboxes. I leveled a rogue to level 60, so she could fly, discovered fly hubs of New Kargath and Chiselgrip and set my main at Tarren Mill. New Kargath is the closest Horde mailbox to Blackrock Stronghold, where I farmed junkboxes, it also provides a flight path from Tirisfal Glades, where zep from Org falls ashore to Burning Steppes zone. So my rogue would farm boxes, hop to Chiselgrip, take public transportation to New Kargath and send mail to my main. Main was stationed at Tarren Mill, short fly from Ravenholdt Manor, where boxes are dropped in exchange for the Ravenholdt reputation. I tried Blackrock dungeons for farming and didn't like them much - a hassle to get in and out, farming outdoors is much more convenient. Full round of 4 mob groups and scattered singles got me between 9 and 22 boxes.
/cast [@mouseover] Pick Pocket
Overall not an exciting experience and requirement to have a rogue really annoyed me. I know I could have just buy junkboxes from rogues, but I didn't have enough luck with the guildies and didn't want to go to trade channel. I guess I am more of a DIY guy.