This is a good thread. I think we can look at a few things to get an idea of Machida's TDD, as both the OP and other posters have implied. Also, the Shogun quote regarding Machida's TDD is interesting. One thing I do know about Machida's base, which can perhaps be some sort of correlation with the level of his TDD is that he did practice sumo. I also believe he held some sort of title in it. If that is true, which I'm fairly certain it is -- I don't really have the time to check sources but I believe I have before, it would say a lot about his TDD, because so much of sumo is based on positioning and keeping a solid base.
It also has a very deep level of competition because, not only has it been around for a really long time but there are so many practitioners, that high-level sumo would definitely be something to consider.