Possible? Not sure.
Gonna happen? No.
Remember, there are people who like Hillary, who are currently getting a lot of attention -- and people who DON'T like Hillary, at all. JPB is an example of a member here who is leaning Obama but would be put off if Hillary were VP. There are many others who share her thinking.
So while Hillary would gain a certain number of people if she were VP -- she'd lose some too. I think Biden nets more votes. (And that's just in terms of existing supporters -- I think Hillary-the-VP wouldn't help Obama as much as Biden will help, in terms of actually campaigning.)
First Read today:
*** When your staff doesn’t do you any favors: All that said, who in Hillaryland thought it was a good idea to step on the best speech of her political career by giving blind quotes about a future presidential campaign? She got tremendous accolades from Team Obama, but some Clinton staffer had to spill beans about the speech's motivation to the New York Times. “Mrs. Clinton is almost certain to run for president in 2012 if Mr. Obama fails this time, several Clinton advisers said Tuesday, and any such plan could possibly founder if the Clintons’ negative feelings show through this year.” It's actually a good example of how no good deed goes unpunished by her staff, and it’s another reminder of how undisciplined her campaign would be right now had she won the Dem nomination. It's no wonder there's so little trust between the candidates when staff -- particularly hers, in this case -- undermines her unity efforts.