Finishing my elite...
The Hidden Elite Four of Sinnoh
Elite Four Birch
Grass and Bug
Kriketune Lv 78
Sceptile Lv 76
Venusaur Lv 79
Torterra Lv 75
Yanmega Lv 78
Vespiquen Lv 77
Starting Speech: "Hahahaha! I will defeat you in the name of Hoenn!"
Ending Speech (Birch win): "Hoenn is victorious yet again! AHAHAHAHAHAHA!"
Ending Speech (Birch lose): "What?! No! Well, I best not dream too far ahead. Good luck, trainer."
Ending Speech (draw): "Hmm..... we both did our best."
Ending speech (outside, if you win only): "Well! I believe you can progress to the next level. Be warned though, trainer! Elm is ultimately tougher than me. He is devious. Take care of yourself, and take this. It's a Fire Stone. It will evolve an Eevee into Flareon, and a Growlithe to Arcanine. Take care."
$5,000 and a Fire Stone
Elite Four Elm
Dark and Ghost
Conditions: Challenger must not use Dark, Ghost or Physic-type Pokémon.
Banette Level 78
Gengar Level 80
Spiritomb Level 70
Dusknoir Level 79
Froslass Level 81
Drifblim Level 78
Starting Speech: "Ha! Birch was a weakling compared to me. Prepare to face the might of Johto!"
Ending Speech (you lose): "Johto is too powerful to be defeated by one of the Sinnoh weaklings!"
Ending Speech (you win): "That was a good fight. We need to fight more often!"
Ending Speech (draw): "How could this happen? I never expected this..."
Ending Speech (outside): "Well, prepare to meet the professor that represents your region. He is powerful to be sure, he defeated the Champion! Take this Dusk Stone, I don't know what it does, but it makes a Mismagius, I heard... now go! Take these Full Restores as well and go win, trainer!"
$5,000, a Dusk Stone, 6 Full Restores, a Strategic Badge (which will let you into a hidden bit of the Battle Frontier which enforces strategy) and unlocks the PokéFlute on your radio!
Elite Four Rowan
Infernape Level 85
Charizard Level 87
Blaziken Level 83
Typhlosion Level 89
Magmortar Level 86
Ninetales Level 90
Starting Speech: "Dare you challenge me? Are you sure? Because all my Pokémon have a special move, Bone Crusher, which will level down your Pokémon by TEN LEVELS!" YES/NO
If yes: "Well, don't say I didn't warn you!"
If no: "Go die in a hole." *player is transferred to the Secret Compartment, where they face a Double Battle with Elm and Birch before coming back*
Ending speech (you lose): "I did warn you, after all."
Ending speech (you win): "See how varied movesets can be an advantage yet a downfall?"
Ending speech (draw): "I refuse to let this happen. You must battle me again!"
Ending speech (outside): "Right, take this Leaf Stone and Shiny stone and go. I warn you...."
$5,000, Leaf Stone and Shiny Stone
Elite Four Oak
Froslass Level 95
Mamoswine Level 99
Walrein Level 94
Dewgong Level 97
Lapras Level 98
Jynx Level 96
Starting speech: "Are you feeling the cold already? Not to worry, I shall warm you."
Ending speech (you lose): "I hope you get back here, you have been a pleasure to challenge."
Ending speech (you win): "I see where I went wrong. I will learn from my mistakes. I hope you, too, will learn from your mistakes."
Ending speech (draw): "It was so close. The tables could have turned, but instead we resulted in a draw."
Ending speech (outside): "Take these Full Restores and take a Max Revive. You will be glad you have them soon."
$5,000, 12 Full Restores and a Max Revive
Champions Dawn & Lucas (for this double battle, Rowan will join you)
Mamoswine Lv 100
Togekiss Lv 100
Piplup Lv 100
Buneary Lv 100
Pachirisu Lv 100
Cyndaquil Lv 100
Magmortar Lv 100
Clefairy Lv 100
Kadabra Lv 100
Alakazam Lv 100
Clefable Lv 100
Infernape Lv 100
Starting Speech: "Let's dance!"
Ending Speech (all): "That was fun!"
Starting Speech: "Alright! I'm going to beat you!"
Ending Speech (all): "You're tough!"
$30,000 and 30 of every berry