Cosmo: I think we may be arguing type specifics. A heavy A340-300 will not unstick at 10 NU , with the correct eye position forward view is lost and finally a tail scrape will occur at 14 NU with the oleos compressed! I am suggesting to you that not all rotations are done at the ideal constant correct rate. Tailscapes do happen from time to time so. ....... how do you protect yourself from this with possible gusty conditions or the over enthusiastic F/O who gives it a " hefty heave ho" around the 10 NU mark? Next time you get a chance watch a B747-400 take-off. The rear fuselage often gets to within 1metre of the runway even on correctly flown, ideal takeoffs.