It is important to understand that headhunters (executive search firms) get paid by the investment banks when they place people at those firms.  The implication of this is that headhunters want to spend their time on people who are likely to get hired, and those are going to be people with prior banking experience:  lateral hires.  So it’s not to say that a headhunter will never be helpful to someone without banking experience, but this occurs pretty infrequently.  Bottom line, it can’t hurt to give headhunters a call, but don’t hold your breath.