Showtime, Lionsgate and Spitfire Pictures are putting together their own high school musical, but in the form of a feature-length documentary depicting real students, faculty and high schools.Docu, written and directed by Barry Blaustein (“Beyond the Mat”), follows the students of three southern Indiana high schools as they compete with one another to produce a musical that will get them into the Intl. Thespian Festival. Although there’ll be musical numbers in the 100-minute doc, Blaustein said viewers will also get offstage glimpses of some of the students, their parents, teachers, school administrators and even local politicians. Pic will also reveal the backbiting and tension that goes into the process of putting on a musical. Lionsgate plans to flog the movie through the festival circuit and, depending on the reaction, will either release it in theaters or engineer its world premiere on Showtime. Blaustein is co-producer with Spitfire’s Nigel Sinclair, who produced “No Direction Home: Bob Dylan,” directed by Martin Scorsese. Exec producers of the docu are Spitfire execs Guy East and Tobin Armbrust.