True crypt hidden volume.
What bitcoins?
Not just that.
Encryption + stenography + not telling anyone you own bitcoins =
safe from confiscation
That's fine if you never want to spend the coins. But if some confiscation went into effect you're now forced to do all your dealings on the black market even if your coins aren't actually confiscated. Given that, I think if it went down like the gold confiscation, where the government actually gave you fair market value and sent the bitcoins to the Fed, many people would take the deal.