Speaking to schmoes know, elmayimbe of Latino Review, said that according to his sources Detroit would be used to portray Gotham City in Man Of Steel in order to get an edgier Batman. The second location that would be used will be in Morocco. El Mayimbe theorizes that it is the possible location of a Kryptonite debris. Warner Brothers has had major productions there before with Proof Of Lies and also Inception.
http://www.youtube.com/watch?v=wiR_kKCVYZk