Just a hunch.

I predict that Hillary will concede in the week after March 11th.

She is looking like she won't do so hot on March 4th. Then you have Wyoming on March 8 and Mississippi on March 11th. I think Obama will win these, and it will look like a long hard road ahead to Pennsylvania. The money will be running out and people will start calling her asking her not to damage the party's chances. And she knows that a concession at that point would precipitate a sigh of relief that a disaster at the convention would be averted. In fact, she would come out of it smelling like roses and maybe even clinch a nice position (Sec of State?) in an Obama administration. Who knows...

Somebody owes me a Coke if I'm right...