At the Microsoft event in Tokyo, it was announced that Samurai Shodown: Edge of Destiny (Samurai Spirits Sen) would be coming to Xbox LIVE Arcade.
The 3D fighting game was developed by K2 LLC and is being published by SNK Playmore. It's slated for Xbox LIVE Arcade sometime this year.
Update: SNK Playmore has contacted us, letting us know that the Japanese site reporting this incorrectly stated that the game was an XBLA title. Rather, Samurai Spirits Sen will be heading to Xbox 360 as a packaged title in 2009.