There may have been a stray baron or two who got lost and ended up in Costa Rica, but just about everybody else in the way of nobility and global society was in Mexico for the weekend. The occasion was the opening of Las Hadas, a new $35 million resort village on the Pacific Coast that seems destined to become a dilettantish Disneyland for the international jet set. The resort's owner, Bolivian tin magnate Antenor Patiño, says his snow-white village will "set the pace of a new Riviera." A few of the guests muttered about a lack of hot water and one joked that the buildings looked as if they had been designed by "a mad Mexican pastry chef," but most guests found it pleasingly opulent and worried more about things like finding appropriate guyabara shirts. Said heart surgeon Dr. Denton Cooley, who is supposed to know about these things, "Las Hadas may not make you live longer, but you will certainly live happier."