I try to figure out a pattern for this (left one)

You can look at the details here
http://www.anthropologie.com/anthro/catalog/productdetail.jsp?_dyncharset=ISO-8859-1&_dynSessConf=1005105443340556365&id=71607&parentid=APP_SWEATERS_COATS&pushId=APP_SWEATERS_COATS&popId=APP_SWEATERS&sortProperties=%2BmarketingPriority%2C-saleDate&navCount=196&navAction=poppushpush&fromCategoryPage=true&selectedProductSize=&selectedProductSize 1=&color=tau
I have some basic ideas about the construction but I am not sure about the stitches...
I know how to make bell sleeves, I think I can do the hood, adding some ruffles ... It might be easier to start from a fitting basic pattern ... any ideas?
Anyone who would like to develop a pattern with me? Anyone who has an idea about the construction of other parts of this?
What about something like a pattern-along (followed by a knit-along?)...


























