Krisztián in Hungary shares his video of his Baró. He was driving about 30 km/h, or about 20 mph.
"The Kuvasz moves like a wolf with much agility, freedom, ease, elasticity and light-footedness. His gait is powerful, outreaching, graceful and rhythmic without any side swing of the legs and body. His feet travel close to the ground, and as the speed increases they angle under the center line of the body, almost single tracking. At a trot and fast gallop the Kuvasz seems to glide with minimal up and down movement of the body. This effortless movement makes him capable of trotting 15 to 18 miles without tiring."
From: Kuvasz (How to Raise & Train) by Dana I. Alvi and Leslie Benis; TFH Publications, U.S. (October 1976).