More info on the missing Malaysian Airlnes Boeing 777, and a cool map based on last known contact.
The southern arc seems like a very long way to go to commit suicide.
My current virtually baseless guess - the plane flew north and was shot down by China, which is now intent on keeping that news as their little secret. The plane would probably have passed over Myanmar, which seems to have an air defense system capable of tracking a missing Boeing, but would their government be forthcoming with their data, especially if the Chinese were urging them to keep it quiet? I don't know.
And with the current drama over the crimea, is the US going to be the one to point the accusing finger at China, even if we had proof, which we probably do not?