Do not you think it would be better to make a Pokémon Mod for GTA Vice City?.
Just imagine to "Ash Ketchum" looking all over Vice City to rare Pokémon (Pokémon replace the cars) and good trainers who fight (citizens), there are airplanes in the sky but if you change models and you put a Ho-oh or Lugia or Rayquaza, you create different Regions like: Kanto, Johto, Hoenn, Sinnoh, Unova. It might seem a world Pokémon!
Also that the Mod has some missions where you have to help Pokémon, for example when you get to the "Pokémon Center" you speak with Nurse Joy and she will give you the mission to help Pokémon in danger.
You could change all city buildings for forests and mountains that are completely inhabited by these creatures.
Create Pokémon Gyms with good leaders and give you a medal when you defeat them and when you can get the 8 medals participate in the major leagues in each region.
I think that would be the best mod of all !!!
Also do not have to create the cover of the game because there is already in Internet: