The Collaborative International Dictionary of English v.0.48:

Melodist \Mel"o*dist\, n. [Cf. F. m['e]lodiste.]
   A composer or singer of melodies.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "melodist":
   Heldentenor, Meistersinger, alto, aria singer, arranger,
   ballad maker, balladeer, balladist, balladmonger, baritenor,
   baritone, bass, basso, basso buffo, basso cantante, basso profundo,
   blues singer, canary, cantatrice, cantor, caroler, chanter,
   chantress, coloratura soprano, comic bass, composer, contralto,
   contrapuntist, countertenor, crooner, deep bass, diva,
   dramatic soprano, ethnomusicologist, harmonist, harmonizer,
   heroic tenor, hymner, hymnist, hymnographer, hymnologist,
   improvisator, lead singer, librettist, lieder singer, madrigalist,
   melodizer, mezzo-soprano, musicographer, musicologist,
   opera singer, orchestrator, prima donna, psalm singer,
   rock-and-roll singer, scorer, singer, singstress, song writer,
   songbird, songsmith, songster, songstress, soprano, symphonist,
   tenor, tone poet, torch singer, tunesmith, vocalist, vocalizer,
   voice, warbler, yodeler