In large pot, cook and drain pasta according to package instructions; keep warm.
In large skillet, cook bacon over medium heat until crisp, stirring occasionally. Remove bacon to paper towels to drain, reserving 2 tablespoons of drippings in pan. Stir flour into drippings; cook 2 minutes on medium heat, stirring constantly. Whisk beer into flour mixture; cook until thickened, stirring constantly. Stir in cream; cook until thickened, stirring often. Reduce heat to low; stir in cheese, dry mustard, pepper, and 1-1/2 teaspoons chives. Stir in cooked pasta and bacon. Spoon pasta mixture into 9 in. x 13 in. oblong pan.
In medium bowl, stir together melted butter and breadcrumbs. Sprinkle over pasta.
Bake 18-22 minutes or until crumbs are lightly browned. Sprinkle with remaining 1-1/2 teaspoons chives.