There was a try for a HN-like specific to Europe news, hackful.eu but it is not really active
Yeah, activity is the problem if do a HN-like site because the community of HN is great and can't be copied. So I wonder whether there are any sites which segment the articles in HN. And also it can be the window to show the community what happened in that segment(country).
BTW, for HN-like specific to China, tea.tisiwi.com is another experiment.