Tangerine, a WPF Exemplar...

Infagistics has created this WPF application called Tangerine  and they have documented a bit of the process ( requirements, architecture, lessons learned, etc.) ...  

I only peeked high level through the documents, but they seem quite fair and insightful ...  

I wonder if people find these references more helpful  than smaller articles ala code project ...  { I keep dreaming I will soon make time to write one of these ... if only I was more organized  or effective with my time :( }