OK, a little research and here is a list.

1931 - Bill Doyle (Kansas State) 145 lb National Champion (Douglas HS)
1938 - Dale Scrivens – (Oklahoma State) 155 lb National Champion (Wellington HS)
1954 - Myron Roderick (Oklahoma State) 137 lb National Champion (Winfield HS)
1955 - Myron Roderick (Oklahoma State) 130 lb National Champion (Winfield HS)
1956 - Myron Roderick (Oklahoma State) 130 lb National Champion (Winfield HS)
1985 - Melvin Douglas (Oklahoma) 177 lb National Champion (Topeka-Highland Park HS)
1986 - Melvin Douglas (Oklahoma) 177 lb National Champion (Topeka-Highland Park HS)
2004 - Zac Roberson (Iowa State) 133 lb National Champion (Blue Valley NW HS)
2013 - Kendric Maple (Oklahoma) 141 lb National Champion (Wichita Heights HS)