I was actually searching for something similar to what you're talking about. Found this post:
http://forum.bitcoin.org/index.php?topic=5194.0 Mostly details on encryption w/ truecrypt (awesome program btw).
I would think bitcoin clients would offer a great benefit to users by offering this as a feature. Encrypt/Decrypt your wallet, choose what encryption method you would like, set secret key etc.....I guess it would end up looking just like TrueCrypt's interface