Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
Despite research done on XD's and Colosseum's RNG, the only practical way to capture flawless Pokemon is to hack the seed on an emulator. This is for all intents and purposes hacking.
This goes for all Pokemon that are obtained via RAM hacking.