Our Lady of Mepkin was created by Lorenz Perfferly (1903-1955), who was born in Bavaria and lived in Hyattsville, Maryland, outside of Washington. He trained in Nuremberg and at the Academy of Fine Art in Munich. Perfferly immigrated to the US in 1930. He became a noted sculptor, creating works for the Basilica of the National Shrine of the Immaculate Conception and the Washington National Cathedral. Interestingly, he also worked on the iconic Marine Corps War Memorial of the Iwo Jima flag raising in Quantico, Virginia. His son, Larry, became a noted wood carver, particularly of carousel horses.
The inspiration for the Our Lady of Mepkin and similar pieces was Notre Dame Sedes Sapientiae, Our Lady Seat of Wisdom, by the French sculptor Henri Bouriché (1826-1906) for the chapel at Sulpician Seminary in Angers, France. I could not determine whether the original exists. However, Bouriché made an exact copy for the St. Mary's Chapel at St. Mary's Seminary and University in Baltimore. This copy likely inspired Pefferly.
Replicas of Our Lady Seat of Wisdom can be found in several churches, including St. James Cathedral in Seattle, Washington; Our Lady Seat of Wisdom Chapel at St Aquinas College, Grand Rapids, MI; Catholic University in Dublin, Ireland; and Our Lady Seat of Wisdom Catholic Church in Oyarifa, Ghana, among many others.