TESOL Quarterly did a special issue on this topic about 10 years ago (the series editor was Kubota). Some of the articles did consider job advertisements as data to discuss the issue of racism in TESOL. You could also see recent discussions pertaining to this issue through autoethnographic studies (e.g. Canagarajah, 2012). Moving away from the 'teacher', there are also studies which had looked at how international schools portrayed themselves (e.g. Tamatea, Hardy, & Ninnes, 2008), and this inadvertently talks about the types of teachers as well.
I know of a sociolinguist who does most of his research through ethnographic studies. If I'm not mistaken, his PhD dissertation was (broadly) on the attitudes of South Koreans towards the learning of English. Data from his study came from transcripts of TV shows, parliamentary hearings and discussions, the homes of South Korean students taking extra English classes, etc.
The topic seems interesting, and there seems to be regular talk about this topic. But! Are we just trying to portray ourselves as politically correct? Or having an awareness of issues? I sometimes feel like it is like one of those "have-to-have" small talk that needs to be maintained in TESOL (e.g. you're the host of a party, and you need to make sure you say hello to everyone who came). For instance, a friend of mine who recently relocated to Hong Kong sent me this link this morning. It is an op-ed written by Andrew Sewell, one of the DRAL speakers this year:
http://www.scmp.com/comment/insight-opi ... -skill-notI am working on something similar at the moment, where I have been following (since June 2017) two English teachers (one Thai and one Malaysian). Both graduated with a degree in English language teaching. However, the Thai has been, and still is, a teacher assistant for a native-English speaking teacher who does not have any English language education background (the Thai teacher has been accepted for a Master's degree in TESOL from a UK institution - she will soon move to the UK, with hopes that when she returns, she can be the home-room or main English teacher, instead of the assistant; The Malaysian, on the other hand, is a supervisor of an American exchange student volunteering as an English teaching assistant (their relationship is not at best terms as the Malaysian perceives that the American assistant is always questioning her views on the English language and its pedagogy). Aside from regular chats with them, and journaling, we are also collecting official public documents from their workplaces as supporting data.
Perhaps field notes could be another source of data?