Just putting this here because it may be of interest to people: http://musicmap.info
It's the result of 7 years of research from 200+ sources. Whether or not this is useful for MB is debatable, but it's certainly interesting.
This is very interesting. One note, though - please use the zoom! I didn't at first and it seemed quite simple...
cool, really. Do zoom and click. Rather detailed, somehow achademic in a way. quality is high and worth considering IMHO.