ELITE management consultancies shun the spotlight. They hardly advertise: everyone who might hire them already knows their names. The Manhattan office that houses McKinsey & Company does not trumpet the fact in its lobby. At Bain & Company’s recent partner meeting at a Maryland hotel, signs and name-tags carried a discreet logo, but no mention of Bain. The Boston Consulting Group (BCG), which announced growing revenues in a quiet press release in April, counts as the braggart of the bunch.