It was not directly stated that it had to be a queen of Tolkien's univers. . .so I shall choose Emma of Normandy or Margrethe I of Denmark.
Actually i am just stalling for time as I cannot come up with an answer. . . .As you might know I have a pasionate love for Galadriel, but as you said she was not queen and neither was Nimrodel which would be my second choise. (really only because I loved "Song of Nimrodel" as it was preformed by The Tolkien Ensemble)
Ok then it must be
Anairė , little is know of her but I really like Fingolfin.