Usually, sold-out shows can be predicted well in advance, and come on the tails of a highly lauded album. Then there are shows like last night’s Land of Talk/The Besnard Lakes double bill where the fan bases have grown steadily, but quietly, and the last-minute sell-out comes as a pleasant surprise. Still, no one seemed more surprised than Land of Talk themselves, whose highly anticipated set was equal parts fulfilling and frustrating. Singer/guitarist Elizabeth Powell…