The MEGA bootloader implements STK500v2 ...
It does claim to support the ATmega128 as well as a number of other "larger" ATmega chips.
My Atmega128, stand alone microcontroller, does not have a bootloader and what I want to do is to write it with a code that have nothing to do with a bootloader. I also want to use an Arduino Uno (with Atmega328p on it) ISP programmer not an Arduino Mega.