I'm nearly completing of a 3.0 version (with enhanced features), which I was leaning towards selling.
Dunno if a free version will be released or not. I heard something about others porting the 2.0 version over, but I don't recall being contacted about it, and don't think anyone's finished yet.
QuizShock is pretty cool, but the only integration it seems to do with vb3 is the user tables. Unlike the quiz hacks we have seen here, it does not do an "Invite" on the forumhome page to get ppl to take quizzes.
It definitely has potential, I am not sure if it is there yet. For $79 I need more. Image integration into quizzes for one.