This weekend, every Canthan boss monster that you slay will be three times as likely to drop a special, or "green," item. The start of this event will be Noon PDT on Friday and the greens will continue to drop at triple the normal rate through 11:59 p.m. PDT on Sunday. Good hunting!

http://www.guildwars.com

So, 3*0=? Perhaps I've just had extremely bad luck, but I had two characters past Shiro and a third into the forest before I got a green drop from a Factions boss (Swiftspell's Staff). Granted, I don't specifically go out to farm any particular boss, but just playing through the game thus far hasn't got me a lot of greens. We shall see how this one goes.

It isn't bad luck... Green items have a very low drop chance in a party, the more people the lower the chance. Also, I think henchmen take up more loot then people.

If your soloing, you have a lot higher chance. I use the E/A Shadow Form/Sliver Armor boss solo, which can be found in the Assassin forums on GWOnline.net It is in the Assassin forums, since it originally was A/E. The topic name is something along the lines of, "Tired of all that 'Assassins can't solo garbage'?"