For cake: Preheat oven to 350°F Butter and flour two 9-inch-diameter cake pans with 1 1/2-inch-high sides; line bottoms with rounds of parchment paper.
Sift first 3 ingredients into medium bowl. Beat butter in large bowl until fluffy. Gradually add sugar, beating until blended.
Beat in concentrate, peel, and vanilla. Beat in eggs 1 at a time. Beat in flour mixture in 4 additions alternately with milk in 3 additions. Divide batter between prepared pans.
Bake cakes until tester inserted into center comes out clean, about 30 minutes. Cool in pans on rack.
For filling: Combine berries, sugar, and lemon juice in heavy small saucepan.
Bring to boil over high heat, stirring until sugar dissolves. Boil until mixture is reduced to 3/4 cup, stirring occasionally and mashing berries coarsely with fork, about 8 minutes.
Chill filling uncovered until cold, about 30 minutes.
For frosting: Beat cream cheese and butter in bowl to blend. Beat in powdered sugar in 4 additions, then orange concentrate, peel, and vanilla. Chill until firm but spreadable, about 30 minutes.
Cut around cakes to loosen. Turn cakes out. Peel off parchment. Place 1 layer, flat side up, on platter. Spread filling to within 1/2 inch of edges. Chill 5 minutes.
Top with second layer, flat side down. Spread 1/2 cup frosting thinly all over cake to seal. Spread remaining frosting over cake. Mound remaining blueberries on top. (Can be made 1 day ahead; chill. Serve at room temperature.).