Well, it appears that this "Anonymous Leaker" character wasn't bluffing, because now he's apparently released something that lets you play Half-Life and Counter-Strike using Half-Life 2's source engine. And he's also supposedly released an outdated build of Counter-Strike: Condition Zero (it's going gold Friday, see yesterday's story) and/or possibly something that deals with Counter-Strike 2. We really don't care to know the details, and we can't exactly confirm this because we refuse to download these releases ourselves. And we of course strongly suggest you don't download any of this stolen material either.
The latest release notes are pretty much devoid of any commentary from the leaker, but they do seem to call into question the existence of a complete HL2 beta. While the notes confirm a HL2 "pre-Beta" isn't currently in circulation, that doesn't necessarily mean that it doesn't exist and won't be released later. It's hard to say.
But I think it is safe to say at this point that perhaps Valve's and Vivendi's previous statement that only "a third of the source code was stolen" was perhaps slightly innaccurate.