[JonnieCache]

>Does anyone know of a way to boot a different OS based on what BIOS password is entered?

http://www.truecrypt.org/docs/?s=hidden-operating-system

[pavel_lishin]

Is anyone concerned about travelling with an encrypted OS - but not a shadow one - and upon decryption, being accused of only decrypting a shadow OS? How would you prove that you're not hiding something?

[JonnieCache]

It is impossible to prove either way.

[pavel_lishin]

Which might prove to be a concern when Evil Men With Sticks are standing over you, trying to make sure you're not a spy.

Sounds like traveling with a wiped drive is the safest alternative.