We report the creation of highly asymmetric lamellar structures with a well-designed miktoarm star block copolymer of the S(IS')(3) type, where S and S' are polystyrenes of different lengths and I is poly(isoprene). The domain spacing can be tuned continuously from 37 nm to over 300 nm when the miktoarm star block copolymer is blended with suitable molecular weight polystyrene homopolymers. Beyond the unbinding transitibn of the lamellar phase, extremely asymmetric lamellar structures were obtained with up to 97 wt % polystyrene, remarkably leaving the poly(isoprene) layers intact at only 3 wt %!