One french site is stating that MGST would mean Metal Gear Solid: Trilogy and would be for remakes of MGS, MGS2: substance and MGS3: subsistence for the 360.
They do not give any source for that info.

source: http://www.jeuxvideo.com/news/2008/00030506-metal-gear-sur-360.htm

^^^lol it was a joke on neogaf

apparently the fell for it lool

Yeah, it should all be speculation as to what exactly this is right now. I wouldn't be surprised if it's some 360 game but for some reason I'm thinking Nintendo.

Mario needs more friends.

This is the rumour that has the most traction ever on the internet, but the least amount of evidence supporting it. That's pretty crazy.

Everything that comes out of Kojima/Konami's mouth is scrutinized to death, looking for some sort of clue that this rumour is true, and what happens, like now, is reaching to the nth degree. It's really worse than the FFVII PS3 demo. Cause at least then, we have a tech demo to work with, this has no screenshots, no nothing. >_>

Snake was in Brawl already. What more do you want?! D:

It's the second time it happens.

The first time, IGN swallowed it whole, including the typo the gaffer made (he called it Metal Gear Triology).

Now jeuxfrance bites the same bait.

So what are the points in favor and against of this being about the 360?

The only solid thing I can see in favor is the color being green.

http://www.neogaf.com/forum/showpost.php?p=13879592&postcount=1093

http://www.neogaf.com/forum/showpost.php?p=13879654&postcount=1121

I'm in tears lol.

That's it.

And apparently the power symbol is that of the 360 too.  (And of the PS3, PS2, my computer, Wii, DSi, and almost every other electronic).

The "!" is used in Metal Gear AC!D, and the "i" can be for iPhone, or DSi.

Most likely Metal Gear AC!D for DSi or iPhone.

A world where Snake and Mario can meet up not to fight, but to play tennis or bowling instead.