There are a lot of people out there who have found ways to get shinies by soft resetting but a lot of people (like me) have found this out after catching almost every legendary!!And i can guess that you are really annoyed as you have got a lot of shinies well heres ure chance for another opportunity.
Step 1. Make sure that your DS calender is on Friday
Step2. Head to the valley windworks.
Step 3. There should be a pokemon outside the building if not go back to step 1.
Step 4. Go face to face with the pokemon and save your game.
Step 5.Press a to enter the battle with the drifloon if its shiny then catch it if not then turn off your ds and enter the battle again until it becomes shiny.This may take a long time.
And finally I have looked through a lot of trade thread shiny lists and not many people offer shiny drifloons or shiny drifblims so it gives the implication that whoever succeds in this method 1st may be the 1st to do it in pe2k.