i was farming rep in the Uplands of Arithi Valley on the syndicate guys but when the lastest patch came out the npcs were gone and the town in EP that you could go n pickpocket the Npcs for Heavy Lockboxes to turn in for rep are gone.
Well you can still pickpocket, and lower blackrock spire is fantastic for that.
Got around 95 lockboxes an hour there myself, you dont need to reset the instance either so you can go on for aslong as you want.
Are a few movies at youtube with routes etc.
Not sure if there are any other syndicate mobs you can still farm up to max honored.