Equestria Online

Equestria Online is an upcoming fanmade 3D massively multiplayer only role-playing game based on the television show My Little Pony Friendship is Magic. It is set to release in late Spring/early Summer.

Features
You will be able to make your very own pony with detailed colorization and its own cutie mark. You can make your pony a Unicorn, Pegasus, or Earth Pony, each with their own special race-specific abilities. You explore various places in Equestria, like Ponyville.

The creator(s) have stated that you cannot upload your own cutie mark due to moderation issues that would arise. They also have said due to copyright issues that the Mane 6 would not be in the game, which implies that they won't be mentioned. This will probably go for all canon ponies, BG or not.