Oblivion Expansion in Development?

GameSpot is reporting that a The Elder Scrolls IV: Oblivion: Knights of the White Stallion expansion pack was temporarily available for pre-ordering on GameStop.com. That is, until they called attention to it and watched as the retailer pulled it down immediately afterwards.

To add more fuel to the rumor fire, RPGCodex is reporting that Bethesda has trademarked the titles "Shivering Isles" and "Knights of the Nine". These could simply be titles for more plug-ins, but it's possible we might see more than one expansion yet. Only time will tell.