What constitutes a rumor? The inability to cite a reputable source. Who is this guy's source? Someone "high up" that he can't name. Naturally. Why? Because either a) the guy he cites will come out and say "what? He's full of crap." or b) he doesn't even have one. So, take this as you will, but this is a rumor because there's no saying whether or not it's true. There's a possibility, what with more games going multi-platform and the Metal Gear Solid games generally going to other systems (the Twin Snakes remake on Gamecube and MGS2:S on the XBox, for example).
Our buddies at Joystiq took a stab at this also, contacted the editor of Noooz, and got the "I'm 100% confident" speech. You can be 100% confident that you're a male or female. You can't be 100% confident about this. Put on your discussion hats and let's dance!