Hi William,
You can only write 64 bytes at once if they are all in the same page or the address counter will wrap around !! I tackled this issue in my EEPROM lib - http://arduino.cc/playground/Main/LibraryForI2CEEPROM - In the lib I used a blocksize of 16 to keep the footprint [internal buffer] rather small, but it could be 32 or 64. Finally the lib also takes care of writes larger than pagesize automatically.
These features might be usefull.
Rob