I haven't yet tried it, but this place has a version of Japanese-style dan dan mien. Not sure about varieties or quality though…

http://www.yelp.com/biz/beni-tora-los-angeles-3

A second to greggman's rec of Tsujita, as well. They have excellent tsukemen (dipping ramen). Across the street, their second location, Tsujita Annex, has really good tsukemen and their ramen is excellent too, if ridiculously filling.