Hale Smith.

I just read an obituary in The New York Times of a composer who "mixed classical and jazz," a man called Hale Smith who played, arranged and composed for Chico Hamilton, Dizzy Gillespie and Duke Ellington. http://www.nytimes.com/2009/11/28/arts/music/28smith.html?ref=obituaries

Mr. Smith called himself "one of America's most famous unknown composers." As you might have guessed, I couldn't find much of his music online, but I did find one composition, a 12-minute piece performed by the Chicago Sinfonietta called "Ritual and Incantation." It's well-worth the download.