Is Metal Gear Solid coming out on the xbox 360

No. The amount of memory, and the usage of cell processor would make it practically impossible to port it to the Xbox 360
The Xbox 360 doesn't have hddvd (it was discontinued). And uses dual layer dvds, which are about 8 gb. 7 discs (maybe even more) would not be very profitable. And I'm sure the person you know is just blowing smoke out of his %@$. Stop dreaming about things that are not going to happen your console. If you wanted MGS4, then you should have bought a PlayStation 3.

metal gear solid is now on xbox 360 only certain ones only.