I think if Hillary as VP was the deal, it would have been done a while ago, he's got the nomination sewed up, barring a huge negative event that blows him out of the water, and she's committed to helping him, or she loses her future with the Democratic party, and I don't see much for her in the Republican party.
Hillary doesn't balance the ticket in the way a lot of other choices would. She may make a deal for party leadership, or a cabinet position, even Bill Clinton could be in an Obama cabinet, and she can have a nice career in the Senate leadership and be the most influential woman in US history for the rest of her life if she plays her cards right.

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“ The subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state.”

Adam Smith , The Wealth of Nations 1776

"We have always known that heedless self-interest was bad morals; we know now that it is bad economics"
FDR's second Inaugural Address