What would be the best way to put shiny Pokemon into the game?

Shiny Pokemon would be something to have as a prized Pokemon, but they'd have to be extremely rare like the other games. Would making 100% IV Pokemon shiny work, similar to Gen II shiny Pokemon? The issues I see with this are that shinies should be more rare than 100% IV Pokemon, and that everyone would be able to catch the same shiny when it spawns. On the other hand, they could make the Pokemon shiny by a very small chance, ideally 1/8192 like the old games, either for the spawned Pokemon, or unique for the catcher. What are your opinions?