Finally! After more than a few runs through Sunwell (much thanks to my guildies!), the Golden Bow of Quel'Thalas dropped for me and I have my complete elven ranger outfit:
Unfortunately my dark ranger outfit (which I use for PvP) needs 3 more items with extremely low drop rates, so I'm still using placeholder items (which really aren't too bad, considering).
I'll still have to run Sunwell for Thori'dal, of course, but at least I have my PvE set done! :)