Ok, first off, I want to say I'm a total Pegasister and my bronies were the ones behind "PONIES The Anthology."
But sadly, Ponies do not have a place in the contest. When we say "anime-style original animation" we mean things like http://www.youtube.com/watch?v=MvjZ6VkLuCM
While pony panels and such may fly as general entertainment, ponies will not be allowed in the Anime Music Video contest. If we let Ponies in, then we'd have to let every animated show that plays on Cartoon Network, Disney Channel and Nickelodeon.
So while the average person with no knowledge of the awesome that is MLP may think "zomg, their Iz r big so they r animu" that does not make them anime.
So while I totally feel your love for ponies, sadly they won't be allowed in the AMV contest.
EDIT: Also, we don't have any AMVs with american video games in the contest. All have Japanese developers, etc...