Hey, my party got this twice in Maze of Shakhrami while looking for the chest key for RSE... however we got it because the WAR got bored, linked a load of leeches and just pummelled them to pieces... so this does drop from leeches too.
I've hunted Wights for the past three hours, and I've yet to get a Rusty Key.
I've gotten 2 scrolls of Tractor, 2 scrolls of Absorb-AGI, 2 scrolls of Absorb-INT, and 1 scroll of Absorb-VIT.
If you're wondering about the multiple scrolls when they're a rare item it's because I warped to the AH to sell them, then came back for more Wight-death-action.
Windurst quest. The quest is not posted on the site I dont think but you get it from the guy on the roof in windurst waters (Optistery), by telescopes. The quest is called Heaven Cent..I think. I would have to log in and look. The NPC name is Ropunono. He asks for a lens which you find in Ranguemont pass and then you goto maze find key open iron door and get the inscribed constellation coin.