If the Cheonan sinking turns out to be South Korea's Kennedy assassination, maybe Buoy 3 will be the conspiracy theorists' grassy knoll.
Asia Focus has an article up by a citizen journalist, Tanaka Sakai, entitled, Who Sank the South Korean Warship Cheonan? A New Stage in the US-Korean War and US-China Relations.
Tanaka notes a lot of mysterious salvage activity at Buoy 3, a third location near Baengnyeong Island (the bow and stern of the Cheonan sunk at the Buoy 1 and Buoy 2 locations, 6.8 km apart and 1.8 km and 6.4 km, respectively from Buoy 3).
Warrant Officer Han Joo-ho perished after a dive at Buoy 3. His memorial service was held at Buoy 3, and Tanaka speculates that he died in a mission to rescue the crew of an American submarine after a friendly-fire Mexican standoff.
It is difficult to tell where investigative reporting ends and the desire to avoid empowering the conservative ROK government with a 9/11-type narrative begins.
In any case, there seems to be enough ambiguity to keep the Cheonan pot boiling for a long, long time.