I frequent a moble site called flickdirect.com, a movie news site. There's a posting today of a pic taken from a window that overlooks a set, supposedly from TF3....I can't confirm, but seems legit and looks pretty neat. I'm on my phone and can't seem to post the pic, here's the link: http://i.imgur.com/I08MV.jpg
The posting says the pic is taken from an office, I believe in Chicago, I guess where the guy works who snapped it. Sadly, the site where I found it doesn't provide much info.