I'm not convinced that would settle anything. We would need to compare DNG files shot under the same lighting conditions and of the same subject. Then, of course, the pp would have to be done using the same software and in an identical manner. Maybe we need to get several people together for a few days of shooting and comparing (and throw in some good scotch while we're at it).
I'd like to make a subtle point: I think the question is not which is better shooting with identical parameters (namely ISO and shutter speed), but instead, what, given the same scene, are the relative strengths and weakness of each tool given an expert user of each tool.
You suggestion is a laudable one—especially regarding the scotch. I just want to chime in that the practitioners should have the freedom to choose ISO/shutter speed combinations at their discretion, as the goal is to compare the end photograph, not the capabilities at a given ISO. The same should go for post processing. The outcome would be an understanding of how to use each tool to achieve the best possible B&W results.