Let me make this a little clearer for those who aren't familiar with porting games.
MGS4 was developed for like... 4 years straight (5?) as a PS3 exclusive. It's engine is written so close to the hardware as to be essentially inseparable without extreme engineering expense.
Re-engineering such a title would probably cost Konami over 5 million dollars (in dev costs alone -- and then it would have to be re-advertized, manufactured in 6-DVD sets, etc.), over as long as a couple years.
A 360 port? Anything is possible. Profitable? Probably not... not even close. Don't get your hopes up.
On top of that, Konami has something of an old-school Japan sense of business.. I dunno what to call it... honor? Not necessarily good for profit, but they are very into keeping their word, and not upsetting their business associates. If there is some sort of exclusivity deal with Sony, Konami isn't going to be looking for loopholes to break that deal.
