It looks like UMD video dumps work ok then. Only tested this one but nice to know.
Is there an exclusive MGS UMD?
Not sure but I do know I really want to get my mitts on both Metal Gear Ac!d games, they are actually pretty cool.
THE BEST METHOD to run PSX games (and everything else for that matter) is via Retroarch - http://buildbot.libretro.com/nightly/
If you have any questions on how to set it up on Windows please feel free to ask, its very easy.