Yang Chengfu’s earlier book, Taijiquan shiyongfa (Application Methods of Taijiquan), included a section on spear/staff, with photos and some brief explanations. My understanding is that the techniques for spear and staff were essentially the same. Fu Zhongwen definitely worked with staff techniques. I recall an Australian student of Fu Shengyuan relating a story about Fu Zhongwen coming to visit, and going into her backyard to cut a couple of large pieces of bamboo growing there to use for a staff demo.
In a related discussion last year, Jerry linked a page from Chip Ellis’ website that has the photos from the early Yang Chengfu book. The photos are of Tian Zhaoling and Dong Yingjie:http://www.chipellis.com/Pictures/Spear-Set/spear_set.htm
Mr. Ellis also wrote some very good descriptions of his own training in the staff. I would not attempt to learn this from a video; one really needs to learn from a teacher.