It might be a case of diving deeper to find the bands that appeal to a metal fan. The Wall Street Journal (of all places!) had an article on The Weird Global Appeal Of Heavy Metal, the rise of metal in places like Indonesia, Chile, Brazil:

http://www.wsj.com/articles/the-weird-global-appeal-of-heavy...

And then you've got the heavy metal bands in Iran that are far more hardcore, facing jail time or execution for their music:

http://www.metalinjection.net/metal-crimes/iranian-musicians...

I've personally started listening to a lot of German bands - Rammstein helped lead me to Oomph, Unheilig, Eisbrecher, Donots and others. It feels great to love bands that have had #1 albums overseas, and yet hardly anyone has heard of them where I live.