Modifying Wow vanilla...

Is there any way to play on Vanilla.exe with the actual graphics of World of warcraft? Meavy it could some way to modify textures on .mpq files or something.
I know it is possible because i saw in Ownedcore.com (in the Mod section) some people showing old sites of World of warcraft unreachables, as Dr Lapidi Island from Wow Alpha (I still have the sandbox) but with Cataclysm graphics. I could see that because the water had the new textures which were implemented in Cataclysm.
So it meavy could be possible change some textures from the game. Or meavy what i saw it just was a Cataclysm private client with the .mpq file from Alpha wow sandbox. (I know it could be possible aswell because some custom private servers uses .mpq files to make possible their custom content ingame) This is the most probably case.
Anyway, i ask for if anyone knows how to do it.
I know it is possible because i saw in Ownedcore.com (in the Mod section) some people showing old sites of World of warcraft unreachables, as Dr Lapidi Island from Wow Alpha (I still have the sandbox) but with Cataclysm graphics. I could see that because the water had the new textures which were implemented in Cataclysm.
So it meavy could be possible change some textures from the game. Or meavy what i saw it just was a Cataclysm private client with the .mpq file from Alpha wow sandbox. (I know it could be possible aswell because some custom private servers uses .mpq files to make possible their custom content ingame) This is the most probably case.
Anyway, i ask for if anyone knows how to do it.