ethomaz on 23 October 2012
Anyway I found that in B3D.
https://josepjroca.wordpress.com/2012/10/11/nintendo-revela-las-tripas-de-wii-u-ii/
https://josepjroca.wordpress.com/2012/10/12/nintendo-desvela-las-tripas-de-wii-u-iii/
The dude did the diagram based in the board pictures.