The cast of the upcoming sequel to beloved rockumentary This Is Spinal Tap continues to grow. In fact, it has grown so large that, were you to attempt to represent the size of the cast on the volume knob of a guitar amplifier, you might say that it goes to…one notch beyond what you would expect to be the final and loudest notch. In addition to previously confirmed cameos from the likes of Paul McCartney, Elton John, Garth Brooks, Trisha Yearwood and Questlove, Deadline reported on March 26 that Metallica drummer Lars Ulrich and Red Hot Chili Peppers drummer Chad Smith will also make appearan…
