You have plausible deniability for any single disk (assuming their is no info leak through other channels, (and possibly technicalities with TrueCrypt). However

You have plausible deniability for any single disk (assuming their is no info leak through other channels, (and possibly technicalities with TrueCrypt). However, you will have a difficult time claiming that they are all random, especially because you would be set up to run TrueCrypt. The best approach I have heard is to have 2 TrueCrypt volumes, but claim you only have 1. You still have to be careful about data leaks, and making your 'one' look convincing. Also, yes, you cannot be forced to give them your decryption keys.