With this quote Hillary just ended any chance of being the Vice President on the ticket:
"My husband did not wrap up the nomination in 1992 until he won the California primary somewhere in the middle of June, right? We all remember Bobby Kennedy was assassinated in June in California. I don't understand it."
Regardless of what she intended (and I think it revealed a deep-seated subconscious hope she has), placing her on the ticket would mean this comment would be constantly replayed and it would make the possibility of Obama being assassinated a central issue in the campaign.
It was clear in March (to anyone good at math) that Hillary was not going to be president this time around. Now it's clear she is not going to be Vice President either.
My guess is a significant number of her super delegates are telling her she has a week to end the campaign or they will switch to Obama regardless.