. . . oh, the hell with confidentiality.
Unfortunately, the lady is ineligible, having not published citable work in the last twenty-five years (this rule got Robert McCloskey in trouble, too). But think of what Harper Lee has done for children's literature in this country--and, ahem, pursuant to our last discussion, without even a notion of writing "for children." You see her imprint most clearly in the southern coming-of-age tales by the likes of Betsy Byars, Sue Ellen Bridgers, Katherine Paterson and Kimberly Willis Holt; but I think the seriousness and respect with which she explored a child's moral and creative imagination gave real freedom to all juvenile realistic fiction in the last half of the last century.
Lee can, I believe, win the Margaret Edwards award, although I think one of the (shameless) criteria is that the winner must agree to show up and give a speech, which Lee famously does not do.