For the first time, Roger Dubuis has created its Tourbillon Skeleton timepiece in a 42 mm case. Roughly 35 percent slimmer than previous models and lighter in weight, the exposed skeletal design is a showcase for the watch manufacturer’s RD505SQ movement—an intricate flying tourbillon composed of 165 parts. The Excalibur 42 Skeleton Tourbillon ($164,500) features a more refined iteration of the signature fluted bezel and triple lugs that the Excalibur line is known for, and it is available in pink or whit…