Nope, not at Yearly Kos. He was at Transvision 2007, which Roy informs us, will help us live forever provided we like doing it in silicone.
Personally, I have wanted to try some of the new silicone cookwear, which is "colorful, nonstick, stain-resistant, hard-wearing, cools quickly, and tolerates extremes of temperature" -- though perhaps it is a somewhat different kind of silicone that the Transvision people are proposing freezer-wrap my personality.
Anyway, back to William Shatner, who is, after all, Canada's own. A reporter for New City Chicago describes Shatner's appearance:
...as the minute hand moves a good half hour beyond Captain Kirk’s scheduled time of arrival, it’s clear that an excited anticipation has swept over the growing crowd. And while the audience only swells to fill half the small Field Museum auditorium, it’s still noticeably larger than for any of the day’s previous presentations. Finally, a speaker approaches the stage to introduce the man of the hour, and after a short, bizarre video featuring a "Star Trek"/James Bond mash-up to transhumanist lyrics like "We can live forever and make everything better!" Shatner takes the stage.When you think about it, how many other keynote speakers could have come up with that connection?
It doesn’t take long for his cool demeanor and slight self-deprecation to get the audience laughing, and it provides a welcome shot of levity into an otherwise far-too-serious afternoon. Whereas speakers like Philippe Van Nedervelde warned of futuristic Unabombers who would blow the planet to pieces with nanotech nukes—and then went on to propose the use of microscopic cameras to perpetually monitor the population and preemptively exterminate "dangerous" individuals—Shatner keeps it lighthearted (and a lot less horrifying). "Why should any of you care about a science-fiction series?" he asks the crowd before coming up with his own response: "This whole vision of the World Transhumanist Association…very Trek-like."
And if reading this post made you regret missing the whole speech, maybe you need to take The Standardized Should I Stalk William Shatner Test.