The Italian yard has unveiled a limited-edition version of the best-selling 39-footer, which will be produced in just 12 units. The new Riva Cento is a cut above the typical exclusives that builders release to mark delivery milestones, offering both aesthetic and functional upgrades that make it, dare we say, even better than the original.  The open yacht, first revealed at the Cannes Yachting Festival, was penned by Mauro Micheli and Sergio Beretta of Officina Italiana Desig