this is my team for when i go to the Elite Four, their lvl. might be a little off, as well as some of their moves. the ones that i know are correct, i'll post first.(this is in the order that you battle the Elite 4)
1.lvl.83 Heatran,"Heatrage";Fire Blast, Flamethrower,Iron Head, and Earth Power.Item, Charcoal.
2.lvl.71 shaymin,"Flower";Psychic, Magical Leaf, Worry Seed, and Leech Seed.Item, none.
3.lvl.100 Empoleon,"Icey";Bubblebeam, Surf, Cut, and Rock Smash.Item, Quick Claw.
4.lvl.83 Giratina,"Disaster";Shadow Force, Shadow Claw(TM),Earth Power, and Fly.Item,Spooky Plate.
5.lvl.82 Arceus,"Azure";Ice Beam, Refresh, Hyper Beam, and Restore.Item, Icicle Plate.
the last Pokemon is chosen to be at the bottom and hold the Exp.Share; trust me, it is a great way to level up your lvl.40 and below Pokemon, i've been doing it all the time.