Note that the rarity of these Pokémon is high, so you'll need to search a bit. That, or just fast-forward in your emulator! Otherwise, they're still evolvable through trade.
I didn't want to break canon with the official Pokémon games, so they all still evolve the same way. I always intended to add a method that simulated the post-trading process into the game, but I'm pretty sure I don't have the know-how to do that right now.