In an earlier post I mentioned that Serge Harouche (2012 Nobel Prize in physics) is a normalien: a graduate of France's Ecole Normale Superieure. Admission to ENS is strictly meritocratic, based on a competitive exam. The result: 12 Nobel Prize laureates and 10 Fields Medalists from a school with fewer than a thousand undergraduates. (The school is similar in size to Caltech; smaller than most high schools.)
See Defining Merit for the story of Harvard's internal debates of the 1950's, during which a realistic and shrewd admissions dean faced down idealistic faculty committees that wanted to make Harvard more meritocratic.
"Do we want an Ecole Normale Superieure, a 'cerebral school' ... ?"
"What's wrong with Harvard being regarded as an egghead college? Isn't it right that a country the size of the United States should be able to afford one university in which intellectual achievement is the most important consideration?"