These screenshots have recently been leaked and are said to be a real by an 'anonymous source'. I think potentially could be real, the map seems to emulate where the plane was coming from at the end of the trailer and the general look of LA, the screens look high quality, you can see the volumetric clouds/bank building in the background of the ingame screenshots. It looks like the map is unfinished but still pretty damn cool, but it's also possible that this could just be an amazing mod for GTA IV (yet extremely unlikely, especially given how recently the location was revealed). Also if that location is real then we've found a high bump to roof already :ninja:. Here's the original sauce (http://www.dsogaming.com/news/gta-v-map-leaked/).
(http://thumbnails65.imagebam.com/15974/122f7e159737468.jpg) (http://www.imagebam.com/image/122f7e159737468) (http://thumbnails46.imagebam.com/15974/b5f37f159737480.jpg) (http://www.imagebam.com/image/b5f37f159737480)(http://thumbnails61.imagebam.com/15974/538158159737455.jpg) (http://www.imagebam.com/image/538158159737455)