OP mentions truecrypt. If something is encrypted with AES+twofish+serpent or whatever it is(the default setup for truecrypt), isn't that into the millions of years to crack?
The default for truecrypt is AES,
It only depend on the password length, as you may have noticed truecrypt ask for confirmation when using weak password, 14 character is considered weak I think. (very conservative)
When cracking truecrypt one does not process the whole volume to see if password match, only a part at the beginning.
I guess I never really though about the fact that volume size/contents are irrelevant. Teach us more about brute forcing stuff.