I guess the closest are these documents:
http://meta.wikimedia.org/wiki/Wikidata/Introduction
http://meta.wikimedia.org/wiki/Wikidata/Technical_proposal
and the articles linked here:
http://meta.wikimedia.org/wiki/Wikidata/Notes
which are still under development. But you have found these already, so I
wonder what you think is missing? (besides the obviously unfinished notes).
I hope this helps,
Denny
2012/3/18 John Erling Blad <jeblad(a)gmail.com>