I agree M F S "If you were forced to have a low V1 due to V1max being restricted by Vmbe then it's possible that V1 might be 60-70% of V2, in which case your Vref will be substantially above the Vmbe."
that certainly puts a crimp on the margins
Another thought though the Vmbe limts are demonstrated with worn brakes (only 10% of normal efficiency;JAR/FAR)
.........got to run