It runs into the same problem as the xX360NOSCOPEXx set with Agility in that it needs 2 turns of setup to work.One set that you are missing is Dragon Dance.
Kingdra
Item: Life Orb
Nature: Adamant
Ability: Swift Swim
EVs: 252 Atk, 252 Spd, 4 HP
- Dragon Dance
- Waterfall
- Outrage
- Rain Dance
This set more or less focuses on outspeeding the target. In the rain, 269 speed doubled is 538, outspeeding every pokemon in existence. And after a Dragon Dance, being pretty fast. 317 attack can be boosted to an extent after a dragon dance, and sweeping with outrage and waterfall would be pretty easy.