How might one get a local business directory for a niche of a category?

It is easy to white label or launch a hosted directory of local businesses; there are countless providers who can even segment the directory to a specific locality or category (i.e. restaurants, plumbers)

How though would I go about getting a hosted directory of a specific niche within those categories? Say I want a directory of Italian restaurants or barbers but not hair salons. How would you get one?

Is there anyone who can support a global directory and not just U.S.?

I'd look into pulling from the Google API. I'm not sure it supports categories, but it's worth looking into. You might need someone tech-savvy to do this, but it'll help you grow quickly without having to do a lot of data entry. I've talked with a startup that does something like this for restaurants and I think they pull their data from somewhere. I asked them now, I'll let you know when they get back to me.

Here in Canada, you can use Dunn & BradStreet to provide such directories, but there is a cost. If you know exactly what kind of listing you need, however, this can be very useful, as they can provide you not only with names of businesses, but with contact names as well at those companies.