Anyway, Smealum posted this http://postimg.org/gallery/d7fl5254/
All 980 models of all Pokemon including forms and gender differences. It's not perfect as some models are buggy without animation data.
From what we can get from those pictures:
1. Hoopa has a little orb thingy under its body.
2. Mega Latios and Mega Latias are the same size.
EDIT: Regarding 2, he said the models in the pictures are somewhat "Normalized", meaning you can't tell if they're a different size or not. Like, if you saw it, there are two pikachu models where one is bigger.
EDIT 2: We also have a screenshot of shiny Volcanion from Smealum's twitter. Not really a fan of the pink..
https://twitter.com/smealum/status/432248030960431104/photo/1
It seems to be a trend where they mess up Red pokemon and give them puke yellow like Groudon and Scizor.
EDIT 3: We also have Shiny Mega Latios and Mega Latias, as well as Shiny Xerneas and Shiny Zygarde. Check his twitter.