Are you distinguishing between "I found that there are no" and "I didn't find any so far"?
Which ones that came close have you rejected, and why?
I don't remember the names of all projects that I've looked at, but the main ones were Nutch, Hetrix, scrapy and crawler4j. I've come across several companies/startups that have built their crawlers in-house for the same reasons (e.g. http://blog.semantics3.com/how-we-built-our-almost-distribut...).