Occasionally, there comes a band where it’s hard to believe that so many people could come together and manage to be on the same musical page. If I was told that there are seven people in the world who want to make a gypsybilly band, I would scoff, but this is New York after all. Though Butcher Knives are based in Brooklyn, its members hail from all around the world, which is what gives the band its ethnic sound. The seven-piece group, complete with accordion, will be playing the Knitting Factory on May 17, alongside ska band Mustard Plug.