Before I even START, nothing has been officially announced. My information comes from http://www.ripten.com, who has been pretty good about publishing rumors that turn out to be true. They claim their source is, and I quote

MGS was spied by our contact on on PartnerNet, the developers-only Xbox Live network used to beta-test unreleased downloadable Xbox 360 games.

Metal Gear Solid has long been recognized as one of the greatest games of all time, basically re-writing the rules on how games work. Now approaching it’s 10 year anniversary (along with the series 20th anniversary), a re-release on a new platform may seem fitting.

So far, Metal Gear Solid has appeared on the PS1, Gamecube (Completely remade with THEN next-gen graphics) and the PC. Interesting enough, Microsoft themselves were the ones who ported MGS over to the computer, so the idea of them appearing on another one of their platforms isn’t TOO far-fetched. Metal Gear Solid 2 also made an appearance on the Xbox during a re-release of the game.

The source goes on to say that the project has been hit with a few unspecified road bumps.

I can’t imagine what problems there’d be, especially if we’re talking a port of the PC version, as opposed to something pseudo-bleem!-ified via PS emulation. Unless we really are talking the original PS version and the problem has to do with emulating Sony hardware, whether literally or legally, on Xbox 360 turf. Color me clueless either way, and treat this as hearsay until Microsoft says it all official-like.

There is an issue with space however. Metal Gear Solid required two discs, and those discs added up to weigh a hefty 1.3 Gigs. Even with the most recent upgrade in the XBLA, games can only take up 350 mb of space.

Compression has come a long way, I have MGS on my PSP (Custom Firmware of course) and during the conversion process was able to get the first disc down to about 390 mb.

What do you think? This rumor got any weight to it?

SOURCES:
http://blogs.pcworld.com/gameon/archives/007085.html
http://www.ripten.com/2008/06/09/rumour-metal-gear-solid-coming-to-xbla/