Still going to wait for official word from Microchip, but @Andrew Macrae pointed me down the right road. It seems that the EEPROM status bits (EECR) are controlled by the calibrated internal RC oscillator; its also utilized for SPM instruction cycles as well. So it seem the internal RC oscillator is quite pervasive in the function of the chip as a whole, even if it is not used for the system clock.

Still going to wait for official word from Microchip, but @Andrew Macrae pointed me down the right road. It seems that the EEPROM status bits (EECR) are controlled by the calibrated internal RC oscillator; its also utilized for SPM instruction cycles as well. So it seem the internal RC oscillator is quite pervasive in the function of the chip as a whole, even if it is not used for the system clock.

EDIT: the information provided in the datasheet seems to contradict the answer provided by Microchip... but hey, they make the darn thing.