There's a lot of "accent reduction" work done around telephone support centers. It is big business in various places, Bangalore, India being a major one. Microsoft & others regularly advertise at Dave's & elsewhere for such jobs. They want TEFL certs & experience plus willingness to work long weird hours. Money is good for India. Somewhere there must be a forum for those teachers. If you can find them, they likely have much info.
This reminds me of a story. A big concern for some Canadian school boards is how to teach "standard English as a second dialect", mostly meaning getting Caribbean immigrant kids to lose various aspects of the language that make Canadian teachers gnash their teeth. A British guy I knew was a well-known player in the development of the ESP approach (obit http://www.eisu.bham.ac.uk/timjohns.shtml
). He got invited to Canada to do a summer course for high school teachers on SE as a S Dialect.
First class, he explains that he cannot teach them anything about teaching technique; they probably know at least as much as he does. Maybe a bit about how modern linguistics views language. However, the most important thing he can do is let them know how their students feel. He will therefore conduct the entire course in Black Country English, expect them to use it, and correct them whenever they deviate.
Black Country is a dialect from the rural area around Birmingham, nearly impossible for a North American. In my rather limited experience, the British midlands dialects are harder for us (I'm Canadian) than Geordie or Scots, even though those are sometimes nearly impossible. e.g. Jasper Carrot is much harder to understand than Billy Connolly. Black Country is the worst I have heard.