There are some ditto in Unova! You can find them in a place called the Giant Chasm. But the Pokémon there are pretty strong - you'll have to be tough to go get them!

[He grins his usual grin, looking excited.]

Let's go! Eelektross, Thunder Wave on Ditto! Archeops, Earthquake!

[The electric eel had an ability called Levitate, keeping it safe from Archeops' ground-type attack. The Thunder Wave was aimed at the larger ditto.]