External Audit>FLDP Rotations>FP&A, Controllership, Treasury> CFO
The smaller the company, the less steps seem to be necessary. But most big companies will have you do a rotation in multiple business units or functions.
For the F100, this is kind of interesting: http://www.russellreynolds.com/insights/thought-leadership/where-do-cfos-come-from
Obviously, the larger the company, the more important deal-making and m&a exposure become.
Or, you can leave public accounting and become the CFO of a small startup pretty easily like one of my professors did.