In Jacqueline Carey's Kushiel's Dart, part of the Kushiel's Legacy series, the Allthing is an enormous meeting of the heads of all the tribes of Skaldia. Though most of the persons present are male, women have the right to speak at the Allthing, won for them by Brunhild the Doughty (likely based on the story of Brynhildr), who wrestled Hobart Longspear and beat him two of three matches. Allthing is apparently based upon the ancient Scandinavian assemblies called "Thing", and the Icelandic Althing.
Waldemar Selig calls an Allthing during the Bitterest Winter; Gunter Arnlaugson takes twenty of his men and four women, including Hedwig Arnildsdottir. To the actual meeting, the leader of each steading is allowed to bring two of his thanes and his headwoman.