Well, Condi would probably turn her down, so she'd probably have to pick a present or former member of the Congressional Black Caucus. Maxine Waters? Sheila Jackson Lee? Cynthia McKinney? Barbara Lee?
That said, perhaps someone like Rep Donna Edwards of Maryland or someone from the business community like Ursula Burns, CEO of Xerox...or a man like Kenneth I. Chenault, CEO of American Express (I have no idea whether Burns or Chenault are Democrats and would even be interested...just thought I would toss them out there).