So whilst everyone's all gushing over mega rayquayquay, which looks pretty awesome, I think some people may not have seen this video, showing mega ray in a wifi battle.
http://www.youtube.com/watch?v=WCHIjgQRGWw#t=61

Whilst this pretty much kills any hope of customisation seeing the general player avatars and ranger avatar, I really like is that at the beginning when they're in the pokemon select screen, you can hear the remixed Rustboro city theme, as well as clearly being able to hear the ORAS trainer battle music.
As a bonus bit of trivia , the Ray was in a masterball, pic related