It's a rarity in UK history but it has been done.
Adolph Rupp signed 4 in 1971 - Grevey, Conner, Flynn & Guyette were all HS A-A.
Joe Hall did it twice - Bowie, Hord, Minniefield & Hurt in 1979 and Davender, Madison, Jenkins & Lock in 1984.
Rick Pitino, Eddie Sutton, Tubby Smith & Billy Gillispie never did it.
John Calipari signed 4 HS A-A in 2011 - Davis, Teague, Kidd-Gilchrist & Wiltjer.
I think he is poised to do it (again) in 2012. Goodwin and Poythress are likely HS A-A in 2012. Cauley is possible HS A-A but doubtful in my view. Good player, just not HS A-A.
But UK is recruiting (and has 50-50 chances at) several others who are likely HS A-A in 2012 - Muhammad, Stokes, Bennett & Pollard. Odds are good Calipari will ink 2 of them in the spring.