After doing some reading, I come to these conclusions:
Portable generators supplying only cord and plug connected or genny mounted equipment do not need a ground rod if the frame is bonded to the grounding wire-which obviously includes the receptacles. (NEC 2014 250.34) If supplying "premises wiring" a ground rod is required.
Neutral/ground bonding is only required for "premises" wiring-which is permanent OR temporary distribution-ie panels or distros. (NEC 250.26, Art 100 definitions)
I see several references to no connections between neutral and ground downstream of the main disconnecting means. A ground neutral bond can be at the source or the main disconnecting means. Is that "or" enough to preclude both? (NEC 2014 525.31)
I am not seeing a distinction between "less than 5kw" and "larger than 5kw".
Where am I not looking? What am I missing?