I thought about way to hide that I'm using truecrypt on HDD, other than truecrypt built-in decoy-OS feature - it has lots of disadvantages.
My idea is simple: Use full disk encryption on my system drive( which i want to hide), while creating it make rescue disk on usb stick. As can be read on Truecrypt site I can boot from rescue disk without copying bootloader to hard drive.
Then i will erase whole TC bootloader from HDD. I hope such disk under investigation will look like completly unformatted disk.
On second drive i will install unencrypted decoy OS.
Finnaly i will set boot sequence to USB->second drive.
When usb is present it will boot TC bootloader, than booting my hidden partition. Otherwise it will boot from second drive.
It will work as i expect it to? It is even possible? Some hints, pitfails ?