Kinect & motion detection/sensor controllers

One possible answer is that it's "old tech" in the sense of not having changed at great deal (with the exception the release of the "HD" version), and that the Max tools for its use are out there (largely Windows-based) are sufficiently robust that they "just work"....

Historically, there's often a flurry of posting about apiece of hardware when it first appears, and then users get a handle on its vagaries and start using it like any Max external that kicks out useful messages - they do the patching that translates or modifies the messages the object kicks out in such a way that it talks to the stuff they want to control. Although that's useful to know [I spent a bunch of time recently writing a book that focused on that very thing, in fact :-) ], it's not often something that people talk about here. When the hardware interface "just works," users tend to move on to the questions of what they wish to do with the data. If it doesn't, that tends to be the focus of the postings - more narrow use-case situation.

In that case, questions about specific mapping will often not be a matter for discussion here - that bit of patching and control tends to be individual and personal (above and beyond some interest in message-passing efficiency now and then) - as Luke DuBois says, "Mapping is Everything" - and that tends to mean that it remains "secret sauce" for users.

In my experience, the place where the finer points of implementing that connection between hardware and design goals is more likely to appear when someone poses the questions you have in the form of an example patch they're working on and then asks for advice. Those discussions tend to be very interesting, and to actually attract the attention of like-minded individuals to a considerably greater extent than questions that start from zero or are more general in nature. There may be others here whose mileage varies, of course.

In terms of the MYO, perhaps you should google Alexander Refsum Jensenius' work with ensembles that use the device. In my limited experience, he and his group of colleagues and students have done some beautiful work using it. There are probably some NIME papers on it out there, at lease [that's where I initially encountered the work].