Interesting. I am maybe forgetting now, but I don't recall this on any conventional type I have flown - even the B737 Classic. It was always a set pitch. Those aircraft were not the size of a B747 though.
Airbus FBW presumably does use the aircraft mass to calculate a pitch angle for the speed bug and the SRS, speed reference system, to achieve V2+10? But it does not display it as an actual figure for the pilots, who rotate to +15° and when airborne they follow the SRS in pitch.