None of the on-the-ground transhumanists take Ray very seriously. While he might genuinely be attempting to bring about advanced technology, I don't see how "get lots of publicity" is a viable method to reach his purported goals.
He hasn't really worked on OCR since the 70s. Apparently, that's his claim to technological progress. Oh, also he did some electronic noisemakers. Still, I wonder about the 40 years between then and now. 40 years is a long time to work towards transhumanist technologies. But instead he has squandered it into publicity on top of his OCR accomplishments?
There is a growing sentiment among transhumanists that his cheerleading and publicity campaigns aren't going to materialize advanced technology. We have to build it ourselves. But we already knew this, it's just that the "sit back and wait for it to happen" fairytale is very seductive. In fact, that's exactly what people want to hear.
For somewhat-unrelated criticism regarding Ray Kurzweil, there are these emails from Paul D. Fernhout: http://heybryan.org/fernhout/ But to be fair, you can still spot TSiN on random bookshelves when you go to hackerspaces. It's almost cute, really.
Bias: irc.freenode.net ##hplusroadmap ("sponsored by George Church" just like everything else)
> Are there actually transhumanists who actually work on building transhuman stuff?
More than you might guess. There's a lot of participation within the do-it-yourself biohacking scene. Also, RepRap and other open source hardware projects tend to attract transhumanist talent. I don't mean to sound too biased but you should check out that IRC channel I mentioned.