You know that Sony also invested some money on helping Kojima create MGS4. Kojima said that he wanted to keep MGS4 as an exclusive he or the devs wanted a hometheatric console they are going to add lots of cutsceance, extras gameplay and all that crap 10 gigs were not enough and i doubt that the devs are going to delay the game any further for the 360 i mean check out halo if it would be multi it would suck for PS3 since it was designed for the 360 that why the 360 version would be a hit and the PS3 version would be a flop. MGS4 is to advanced in the production changing to multi would ruin the game completely.
FF is also known as a giant RPG game with 30 or more hours of gameplay. Square wanted to switch to Next-gen they would need excellent graphics, gameplay and also make the story mode longer than 30 hours. The DVD9 of the Xbox cant handle all that. If u want to i cane find an article of Square stating that 10gigs arent enough and they wanted to use the full capacity of the Blu-ray disc which is 50gigs on 2 layers.
FF might go multi but MGS4 hell no