You obviously know your stuff. It does looks Peacemaker-ish right down to the two inboard bumps. I assume the spots for the remaining engines would be included on outer panels not seen here.
Parabellum is correct. Here is an XC-99 ( a prototype cargo plane based on the B-36) that has the same wing section. Since the actual wing is 200+ feet long this is as he says, the center section. Good ID. http://maps.google.com/maps?hl=en&q=United+States&ie=UTF8&z=18&ll=29.374168,-98.587044&spn=0.002155,0.005407&t=k&om=1
http://www.b-36peacemakermuseum.org/index.htm
http://maps.google.com/maps?hl=en&q=United+States&ie=UTF8&z=18&ll=29.374168,-98.587044&spn=0.002155,0.005407&t=k&om=1
http://www.airliners.net/open.file?id=0105277&WxsIERv=Pbainve%20O-36W%20Crnprznxre&Wm=0&WdsYXMg=HFN%20-%20Nve%20Sbepr&QtODMg=Sbeg%20Jbegu%20-%20ANF%20WEO%20%2F%20Pnefjryy%20Svryq%20%28NSO%29%20%28ASJ%20%2F%20XSJU%29&ERDLTkt=HFN%20-%20Grknf&ktODMp=Nhthfg%202000&BP=1&WNEb25u=Wnzrf%20Evpuneq%20Pbivatgba&xsIERvdWdsY=52-2827&MgTUQtODMgKE=Ng%20gur%20Ybpxurrq%20Znegva%20cynag.%20Ynfg%20O-36%20ohvyg%2C%20fubg%20bs%20gur%20jvatf%20%28230%20srrg%20jvatfcna%29.&YXMgTUQtODMgKERD=2879&NEb25uZWxs=2000-08-26%2000%3A00%3A00&ODJ9dvCE=&O89Dcjdg=&static=yes&width=950&height=599&sok=JURER%20%20%28nvepensg_trarevp%20%3D%20%27Pbainve%20O-36%20Crnprznxre%27%29%20%20beqre%20ol%20cubgb_vq%20QRFP&photo_nr=21&prev_id=0105278&next_id=0105099
Here is the same link but shorter :
http://www.airliners.net/open.file/0105277/M/