It seems you want more than just deniable encryption, you want steganography.
It is virtually impossible to have perfect steganography, specially if you are already seen by your adversary as a suspect.
Something that could do that would work in most situations is to use an unformatted partition instead of a file. Using Linux is a good idea since there is no truecrypt.exe to raise suspicion.
In the end, it all depends on how often you adversary will have access to your computer, and how eager they are in finding hidden encryption.
Also, keep in mind that some people or offices, if they think you might be doing something that they consider really bad, they may simply send you to places where there is no law, and keep coercing you to give up passwords and keys even if after there is none left.
I suppose this is the best one can do. The presence of the TrueCrypt executable is always going to give away that you have encryption somewhere. Even the 'hidden volume' trick would be of minimal use, since a person who knows how TrueCrypt works would suspect there was a hidden volume in your machine. – RHPT – 2011-11-09T16:55:29.797