Walk Hard is the best example of how to satirize a film genre. It's a great movie on its own but successfully lampoons the musical biopic genre all the way through. You can see they really worked hard on it and it's not just a cash grab like all the "blank" movie titles.
The article perfectly summed up this treasure of a movie.
"Some of the sharpest, funniest scenes play out like the filmmakers took script pages of Walk the Line, highlighted every cliché and then doodled dicks in the margins for good measure."