Some examples of nontraditional paths I've seen:
PhD -> HF analyst -> Sub-PM -> PM
Top Undergrad -> Chip Engineer -> HF analyst -> HF Sub-PM -> HF PM
Top Undergrad -> Oil/Gas Major-> Personal Bankruptcy -> IB for 4 months -> HF PM
Military -> PhD -> NASA -> Retail ->Computer Repair-> Oil/Gas Major -> HF Senior Engineer
Not Top Undergrad -> Reservoir Engineer -> HF Analyst
PhD -> Factory Worker-> Commercial Pilot -> Flight Attendant -> Utility Company -> IB -> HF Senior Analyst
Military -> Consulting -> Oil/Gas Major -> HF PM