Sometimes (every second Friday) I think that the main objective of the US gov shutting down Silk Road actually was to get their hands on a large stash of Bitcoins without affecting the market price at all. They got around 130K coins out of that and they still might get several 100K more if they manage to beat the keys out of the Dread Pirate Roberts.
....
Conspiracy theory stuff this, but well within the realm of possibility I think.
They have already announced their intention to auction the coins off for fiat at some point in the future.
I imagine it will be a while with the blinding speed of the wheels of justice and all....