What is the altitude of the nose vs tail in airplane flight?
Yes that data exists , it is recorded during flight test data gathering for full flight simulators. The transducers used are not two bars altimeters, but direct gravitational angle finders and gyro's for increased frequency response. Sample rate was 30 Hz in the olden days, now 100 Hz or higher.

A full set of measurements consists of correlated sets of


pitch, roll, yaw angle measurements from dedicated mounted transducers; 
angle of attack and sideslip, dynamic and static pressure, magnetic course, and all other parameters recorded by the aircraft instruments;
stick and control surface positions from dedicated mounted transducers.


The aircraft data sets are sold for a lot of money, your best bet would be to try to get your hands on flight data measurements for an older type aircraft or a type that is not produced anymore.

Next time you fly, you could even measure this yourself by using the transducers in your mobile phone, which has acceleration, rotational velocity and angle transducers, plus a set of linear GPS co-ordinates.