Brandon Laurino, Online director for Konami, has replied to a comment on the PS Blog, regarding the possibility of trophies being implemented within MGS4. This is what he had to say :
On the subject of MGS4/MGO trophies and Konami ID – we hear you. We have been circulating these issues internally, and we will report back as soon as we are able.
Stay tuned for further developments on this exciting story!