The Major issue of not being able to dual-boot on TrueCrypt disc encryption systems won't get out of my mind.
My idea is, wouldn't it be possible to create an encrypted HDD with an Windows system on it on a slave HDD and install Linux on another main HDD, then point with grub to the TrueCrypt bootloader as an option in grub boot process?
Maybe you would need to take out the encrypted slave HDD of the PC before installing Linux to not interfere with the TrueCrypt mbr.
Would this work in theory? And how would I make sure that Grub stays superior after the encrypted drive with the TrueCrypt mbr is back in the PC?