That's a great question! I would personally love to see those as well.
I think the reason these lectures are SO fantastic is because Everyone around the world can tune in to watch LIVE and get the full lecture experience (and also a playback). Also, even if you miss the lecture you can still get the full lecture at one easy price.
A lot of the lectures run between three and four hours (sometimes more, ahem Greg Wilson) and either way these lectures are awesome :) We're always working on giving the best so I wouldn't doubt its a great thing to have!