Some unfortunate news has arrived from the Brony Thank You Fund team at Ponycon. As reported over on their Twitter, someone has stolen the giant signed poster that was going to head to the charity auction later. They are asking that people keep an eye out for it and contact them at (603-513-2383) if you have any information on it's whereabouts.
Hopefully something appears soon. It's pretty awful that someone would steal a thing like this from a Charity booth of all places.
Thanks to Frederick for the heads up.