The fatal flaw here is that this guy lost over 90 days (I think that's the lower bound) of liberty without a jury trial. Under this scheme a judge could jail you until you produce the body in a suspected murder, or until you tell the cops where the money is in a suspected bank robbery.
Contempt is a quasi-criminal remedy with severe limitations. SCOTUS will rule from this that contempt confinement for longer than 90 days requires jury fact finding.
Hmm. It's not true to say under this scheme a judge could jail you for not producing a body. This is more like a situation where the judge could jail you for not allowing people to search the spot where they suspect the body is (eg if you won't let police search your freezer). That's something they can in fact already do. That is to say, they have the right (assuming a warrant) to search where they want to search, and if there is a physical protection (eg a key) it isn't covered by 5th amendment and you have to cough it up.
The 5th amendment doesn't bestow a right to prevent the collection of evidence in general. You could argue that this particular person wanted a jury trial they could easily have got that by disclosing the password and allowing decryption.
That said, forcing disclosure of a password is particularly troubling. On its face it seems obvious that he is deliberately not doing that so as not to reveal the incriminating evidence (ie incriminate himself), which is why he is pleading the 5th amendment right not to be forced to do that.
