The name Mel isn't ringing a bell from within Elvis' circle. There are several possibilites though. For Elvis to be able to take the time to personalize an autograph, it would be following a show, most likely Vegas. Mel could have been part of the stage help, hotel staff or even security. Least likely would be just a personalized gift or something given to Elvis, to which he shows graitude by personalizing the autograph. My quess is going to be only "Mel" will know for sure.