The Collaborative International Dictionary of English v.0.48:

Showman \Show"man\, n.; pl. Showmen.
   One who exhibits a show; a proprietor of a show.
   [1913 Webster]

WordNet (r) 3.0 (2006):

showman
    n 1: a person skilled at making effective presentations
    2: a sponsor who books and stages public entertainments [syn:
       showman, promoter, impresario]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "showman":
   MC, auteur, ballyhoo man, barker, callboy, costume designer,
   costumer, costumier, director, emcee, equestrian director,
   exhibitor, impresario, makeup man, master of ceremonies,
   playreader, producer, prompter, ringmaster, scenewright,
   set designer, spieler, stage director, stage manager, theater man,
   theatrician, ticket collector, usher, usherer, usherette