True :-) But Badass comes kinda close to being a documentary of a movie being made, even if it isnt a documentary (its based on the true story of the making of the first blaxploitation movie: "Sweet Sweetbacks Badasssss Song" (Produced, written, starring and directed by Melvin Van Peebles). Mario van Peebles plays his own Father, Melvin, in Badass.
PS: If you ever decide to see Badass, be sure to leave the little kiddies out of the room. There is plenty nudity, among other adult themes.