In a large skillet, cook the bacon until crisp and brown, about 5 minutes; drain.
In a large, deep skillet, heat 1 tablespoon of the olive oil until shimmering. Add the scallions and cook over moderate heat, stirring, until softened, about 3 minutes. Add the wine and vinegar and boil over high heat until reduced to 2 tablespoons, about 3 minutes. Add the cream and cook until reduced by half, about 2 minutes. Stir in the butter; season the sauce with salt and pepper.
Preheat a cast-iron grill pan. In a bowl, toss the shrimp with the remaining 1 tablespoon of olive oil; season with salt and pepper. Grill the shrimp, turning once, until just cooked through, about 4 minutes. Add the shrimp to the sauce; simmer just until the sauce is thick enough to coat the shrimp, 3 minutes.
Toast the kaiser rolls. In a small bowl, whisk the mayonnaise with the mustard and spread it on the top half of each roll. Arrange the bacon on the bottom half of each roll and top with the shrimp and sauce, sliced tomato and the lettuce leaves. Cover with the tops of the rolls, cut in half and serve right away.