After ripping off 10 minutes of melodic, Prince-like guitar solos on a custom-made electric guitar, Christone "Kingfish" Ingram does something perhaps unprecedented in the entire history of the blues: He apologizes for the length of the song. "I know that was kind of long," says the smiling 21-year-old singer-songwriter from Clarksdale, Miss., after a cover of “Empty Promises,” by the late Milwaukee blues guitarist Michael Burks. "That was kind of a spiritual moment. So excuse us for that."