With the double plunder weekend going on, I would advise that you get online today - only one day of it remaining! Yesterday I found the Sabre Of The Inquisition at the Raven's Cove mines on Bequermo, at the four ghosts. It was rather funny - I had just joined up with a crew who had been there for ages, and on one of my early battles I recieved the sabre.
I think the trick is definitely to find a server and area that has/had some people already fighting there. I believe areas are like slot machines - use them for long enough and they'll pay out. This has been apparent on three occasions with me and a friend. I loot a lot with him, as we're online at the same time mostly. The first time this happened was at Darkhart on a quiet server. I'd been looting there for quite a while, and he teleports to me and gets the Lost Sword on his first kill. :P It happened again yesterday, before the double plunder event started. He teleported to me when I'd just got to the mines. I was about to leave, after seeing that there were others there. He shoots a Devious Ghost and recieves the Sharkfang Blade. LOL! And the third time was explained in the above paragraph.
I'm beginning to wonder if loot actually is random. If someone has been fighting at the same area for a long time, you'll get better loot if you join in later. That's why I track what servers Captain Sharktooth uses sometimes. :P Try Abassa sometimes, because as there are almost always people fighting in the main areas (Tormenta, Raven's Cove, Darkhart, Neban), loot will cycle through a lot faster. Drop in whenever you feel like it, and one day you might get lucky.