I am no longer into pythons at all, so I'm not really familiar with who is breeding what or better yet, who is claiming what. I do see ads pop up from time to time however........
I have, however, seen people advertising "Western" type Melanocephalus............ as well as Eastern. Having herped Australia while I lived there, I do have knowledge on how appearances can vary - example, somewhat unique animals from Durack (Port Hedland) and even discernible color variations within the Kimberley itself. Not to charge to far off the subject but among stimsoni, the differences between locales can be shocking.
While I was there I worked with William Messick who, while doesn't frequent any forums, had an extensive locality collection of aspidites - both womas and black heads. If you had asked me 15 years ago to define a "western" type, I would honestly be stumped.
...and still am.
The question is this - is this an accepted descriptor based on appearance or based on the known traceable origin of the animals? If the easterns are not traceable in this country, why are people selling animals as "eastern" type?