Yep! Mike stepped briefly out of the shadows last October and gave a surprise three-hour talk about LuaJIT internals at the Zurich IT Geeks meetup group: http://www.meetup.com/zhgeeks/events/141272252/
He mostly walked through code examples and showed how they are compiled and why. There is alas no video available and only scant notes published on the meetup page.
It was a great evening, but don't worry, nobody became an instant expert on LuaJIT internals from being there :-)