(Not counting Bubble which is stuck in Gen I-II.)
http://projectpokemon.org/forums/showthread.php?28025-BW-B2W2-Event-Shiny-Nagoya-Magikarp-%28JP%29
On March 20, there will be an event in Japan that distributes a level 99 Shiny Magikarp holding a Rare Candy, with the moves Splash, Flail...