I agree, it does seem like a great untapped potential for a rationalist community. The obvious question is, does being a rationalist make you a better founder of a startup? Or, more relevant here, does being a rationalist of LessWrong stripes make you a better founder?
When it comes to programming prowess, I doubt rationality confers much benefit. But when it comes to the psychological steel needed to forge a startup: dealing with uncertainty, sunk costs, investors, founder feuds, etc... I think a black belt in rationality could be a hell of a weapon!
BTW, we having this discussion here:
http://groups.google.com/group/overcomingbiasnyc/browse_thread/thread/3b91c0f4460dca63?hl=en
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.