I've thought about this perhaps a little too much... I'd be the 8th Gym Leader, a Dragon-type user and my top level would be 50, which would prepare the Trainer to start the E4 at level 53-55, and end towards level 62-63. My team would be as follows (including rematch levels, though moves would likely remain the same):
1st:
Dragon/
Flying, Lvl 48/67
Hurricane
Dragon Pulse
Air Slash
Flamethrower
Start at the mid-level of my team (roughly), in order to introduce the Trainer to the atmosphere the battle will take. The pace will be set by this fast Pokémon, and the Trainer will immediately be introduced to a challenge, and will be forced to display the utmost control and dedication to this battle.
2nd:
Dragon/
Water, Lvl 48/68
Hydro Pump
Dragon Pulse
Ice Beam
Agility
Kingdra will be a different fight compared to Noivern, due to the type difference and its versatility compared to a lot of Dragon dual-types. The pace will be slowed to allow the Trainer to demonstrate their control and the bond they share with their Pokémon here.
3rd:
Dragon/
Rock, Lvl 47/66
Earthquake
Rock Slide
Dragon Claw
Brick Break
A different twist to the battle again, but keeping the challenge to the Trainer great. The pace with this Pokémon will be sped up slightly, with Tyrantrum boasting a high Attack stat and utilising a different power to the Dragons before it. The trainer will have to show their knowledge in battle and their ability to act intuitively against this Pokémon.
4th:
Dragon/
Ground, Lvl 49/68
Dragon Rush
Earthquake
Steel Wing
Fire Punch
The aim of the whole battle is to keep the Trainer on their toes, but Flygon will be the biggest test of the Trainer's reaction to an unexpected situation. The moves Flygon knows and it's typing will throw the Trainer off-guard. The test is whether the Trainer can keep a cool head in strange situations and proceed with confidence and determination.
5th:
Dragon/
Flying, Lvl 50/69
Draco Meteor
Fire Blast
Hydro Pump
Dragon Pulse
My final Pokémon, of course with a Mega Evolution too (couldn't not now could I?). This Salamence I own on my AS with a Modest nature to boost Special Attack. This will be the final test of the Trainer to prove their bond with their Pokémon is strong enough to withstand the toughest of challenges they may face. Should they beat my Salamence and I, they will have proven they have what it takes to face up to the Elite Four.
6th:
Dragon/
Fire, Lvl 70
Flare Blitz
Dragon Pulse
Aerial Ace
Flamethrower
This Pokémon would only be present in rematches, just as an added bonus to up my power against the new Champion.
In the rematch the order of my Pokémon may be changed to suit the situation, and I will no longer act as an Examiner of the Trainer's skills but rather as a simple Trainer myself, entering a battle to learn about myself, and my opponent. So that is my team, how the team functions and what my thoughts are about the battles I would have against challengers.