Do you really think if that if PS# and 360 havnt seen a decent game anywhere close to true 1080p (ala resistance, halo, gta, rsv, cod4 etc) cross platform or not, that somehow GTA will have true 1080p.
Even if it did I would question at, as all these other great games dev's have said almost in step that even to make 720p they would have dropped frames or had to drop other processing (rendering, onscreen polygons etc) in order to keep those frames. But somehow MGS4 can do true 1080p....
Keep in mind Im talking about rendering in 1080p not displaying in 1080p.
The handful of games I have heard that do render in 1080p have not really been anything to get excited about. So if MGS4 really does render in 1080p Id ask what they had to cut in order to achieve it, seeing as most other top games/studios cannot.