The Collaborative International Dictionary of English v.0.48:

quipster \quip"ster\, n.
   A person who frequently makes quips.
   [PJC]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "quipster":
   banana, burlesquer, caricaturist, clown, comedian, comic, cutup,
   droll, epigrammatist, funnyman, gag writer, gagman, gagster,
   humorist, ironist, jester, joker, jokesmith, jokester, lampooner,
   madcap, parodist, prankster, punner, punster, reparteeist,
   satirist, wag, wagwit, wisecracker, wit, witling, zany