I really want one!! I was hoping I could get one till I found out the events for them ended. Are there going to be any more coming soon?
As Sun and Moon are coming out soon, it will be highly unlikely that a Speed Boost Torchic event will return.
Of course, Speed Boost Torchics do exist out there so if you ever find somebody who has a Speed Boost Torchic, you can get them to breed the Torchic (if its a male, breed with Ditto; if its female, breed with a compatible Pokemon; 60% chance for both genders to pass down a hidden ability to their offspring) and then you might be able to get one for your own.
Hope I helped. :)
Source: http://gaming.stackexchange.com/questions/219329/how-do-i-breed-pokemon-for-their-hidden-abilities and http://www.serebii.net/pokedex-xy/255.shtml