http://www.ps3center.net/story-1508-Konami-Confirms-MGS-4-For-Xbox-360.html
http://www.xboxcircle.com/xbox360/2008/01/01/rumor-metal-gear-solid-4-to-xbox-360-eventually/
http://xbox360.thegamereviews.com/story-335-New-Rumors-Surface-of-360-Version-of-MGS-4.html
Rumors all over the place. I know this topic has been done to death, but new information is always good to know.