Research Proposal 1

I have a million and one ideas for a research proposal, and I can't seem to decide on one...
Having said that, I am probably going to look into some action research that would be of direct benefit to the school program I am teaching in at the moment...
I have identified some discontent with the team teaching program that is running within the college I am working.
Team teaching is not unique in itself, as it can be found in many forms, and in Japan it has taken root within a number of niches (AET - assistant English teacher, in the JET program for instance).
However, I wish to look at the effectiveness of team teaching in an adult SLL environment, specifically focusing on the overall effectiveness of native-native English teacher, team teaching situation (which exists in my program) vs. native-Japanese English teacher, (which exists in a parallel program within the same organization). The teachers in both these programs have varying beliefs about the suitability of the native-native team teaching situation.
My limited review of the background thus far has been unsuccessful (can't seem to find anything on the native-native adv/disadv). The situation of two native English teachers (two Americans for instance), teaching on different days, but with the same textbook, doesn't seem to have any sound methodological purpose, yet the administration staff (mainly Japanese) seem to really favor it, as well as some ex-students, who say that it was pretty good.
My initial thoughts were that it was beneficial in terms of learning styles and exposure to varying cultural perspectives... This could be the angle that I could take.
However, for the team teachers it can be a logistic nightmare...which makes it difficult to plan lessons and evaluate student performance effectively...

I haven't quite sussed out the details, but this is the direction I am thinking about taking... I am part of the program, so I am an insider, which makes subjectivity a real problem, as with many kinds of action research, not to mention ethnography etc... Yet, I think that this subjectivity can be balanced with grounding of the findings in some way...

I hope that I am on the right track... Actually, my head is in quite a spin at the moment...