An anonymous source claims that Pokemon GO may soon feature a shiny Pikachu as part of an event for the game's anniversary, and claims that this is set to happen within the next week or so. The game first came out on July 5th, 2016, which means that this event would line up perfectly with Pokemon GO's first anniversary. Additionally, an announcement of some sort will reportedly be made at this year's ACM Siggraph convention, a gathering of computer animation and interactivity industry employees. Niantic creative figureheads Edward Wu, Phil Keslin, Dennis Hwang, and Tatsuo Nomura will all be present to give a talk entitled "Evolution of AR in Pokemon GO". This year's ACM Siggraph will begin on July 30th, and last until August 3rd.
This time frame would also tie in nicely to the Pokemon GO Fest, a series of events that kicked off on June 13 with the Solstice event that saw increased numbers of fire and ice Pokemon roaming about, and will culminate in a real-world event in Chicago's Grand Park on July 22. Since Siggraph takes place after all of these events, the chances of the announcement at the convention including something grand to mark the end of the anniversary festivities are fairly high. At this point, however, there is still no concrete information.
Some shiny Pokemon have been unveiled thus far, with Magikarp and Gyarados being two of the more prominent ones, but so far there have been no reports of shiny Pikachu sightings. While some spurned trainers have had wayward Ditto fool them into thinking that they were about to catch a shiny version of the Pokemon series' beloved mascot, the genuine article remains uncaught. Shiny Pikachu has been sitting in the game's code, along with other unseen shiny Pokemon, for quite some time now, which means that it will end up in the game at some point. The anonymous tipster who claims that shiny Pikachu is coming soon may well be a Niantic insider who decided to leak some information, but the story could just as easily be a complete fabrication, as with any other news story involving anonymous sources. Trainers are advised to take this one with a grain of salt, but be sure to check every Pikachu you come across; shiny Pokemon don't reveal themselves until you've clicked on them in the map and gone into catching mode.