Using this, I have made flutes that are in tune over two octaves while allowing many cross-fingerings. The trick to this is a carefully calibrated bore area deviation between the mouthpiece and finger holes, which I achieve by the simple expedient of drilling extra holes and covering them with sticky-tape.
Feels like cheating, really. There's a Chinese flute that perhaps uses the same trick. The Western concert flute instead uses a tapered headpiece, and the recorder uses a cylindrical headpiece and tapered body, to similar effect.