john1993:
as mentioned a crystal cannot be used at that frequency, only an external oscillator. this is confirmed by my own tests. the fastest i was able to get with a crystal was 22mhz-24mhz depending on the cut and caps.moral of the story: if you overclock dont write to flash.
Just set your low fuse from 0xFF to 0xF7 (full swing oscillator) and any reasonable crystal up to 32-something works fine.
As far as writing flash or eeprom, since those writes are timed by the internal R/C oscillator, the clock speed is irrelevant. Have you ever actually TRIED what you posted?