When I saw this drawing in 1997 it made me think of an early F-15A and that is what I had thought of using to make a model of it. Until I opened a model of the J-31 a while ago. I think the XXJ drawing is what became the J-31. Photo from a similar perspective of a J-31 model from an eBay auction of the seller listed in the bottom corner of the photo.
hesham said:Hi,
and the XXJ from Flightglobal in 1997.
http://www.flightglobal.com/pdfarchive/view/1997/1997%20-%200619.html