Your point doesn't really make sense, though. As is often brought up in this discussion: see the example of Hushmail[1]. If you don't provide your own encryption mechanism, you cannot trust it, which is what Evbn is saying, I think. That's why it makes no sense as a Lab offering (and I'm not sure which is the worst option: encrypting the email in a browser via javascript or encrypting it after it's on the mail server and out of your control).
And of course you can use PGP with almost any email system right now. Just download thunderbird and enigmail (or whatever is the good one these days) and use gmail through IMAP.
