@Thomas,
Since osso is likely to vote for whomever the Democrat candidate is in 2016, I would like to see her organize a movement to draft Jesse Jackson Jr. as I'm sure he's too modest to make a bid on his own.
Since she believes she is to the left of Hillary Clinton then Elizabeth Warren seems her best option. She could consider the oily Martin O'Malley of Maryland, but osso is essentially a very nice person and O'Malley is a nasty piece of work.
Limiting the field to people who are believed to have an interest and a chance, I would hope osso threw her support to Mark Warner.
If she prefers a female candidate, Amy Klobuchar.