I've had moderate success with this team so far. Had serious trouble with scarfed Thundurus in a tournament last week, and Greninja gives me grief sometimes.
Anyway the general strategy is to hit fast and hard. Feel free to dissect and such, I would appreciate some feedback :]
Archeops @ Leftovers
Ability Defeatist
Jolly Nature (+Spe, -Sp.A)
252Atk 252Spe 4HP
Roost - Iron Defense - Head Smash - Ally Switch
STAB Head Smash wrecks, and outspeeds a lot of opponents due to Archeops' base speed of 110. Iron Defense and Roost help counteract Defeatist ability and defend against Rock Slide. Ally Switch for shenanigans, can be used to sacrifice low HP Archeops and give teammate an extra turn. Other possible items are Enigma Berry or Yache Berry to help against Ice Beam.
Mismagius @ Assault Vest
Ability Levitate
Timid Nature (+Spe, -Atk)
252Sp.A 252Spe 4HP
Hex - Icy Wind - Energy Ball - Power Gem
Icy Wind for speed control, Power Gem and Energy Ball for coverage. Hex is a bit of a gamble, but can dish out much more damage than Shadow Ball with proper setup. I used to run Choice Band to sweep with Hex, but it never worked out like that.
Heliolisk @ Focus Sash
Ability Sand Veil
Rash Nature (+Sp.A, - Sp.D)
252Spe 252Sp.A 4HP
Signal Beam - Hyper Beam - Glare - Thunderbolt
Nature is Rash because I used to have Silk Scarf on Heliolisk to maximize Hyper Beam damage. Going to rebreed for Timid Nature. Signal Beam for coverage and potential confusion. Glare for speed control and to set up for Mismagius' Hex.
Crobat @ Life Orb
Ability Inner Focus
Nature Jolly (+Spe, -Sp.A)
252Spe 252Atk 4HP
Taunt - Cross Poison - Brave Bird - Tailwind
Crobat's Taunt is probably the single most important move on this team. Outruns damn near everything and disrupts a lot of strategies.
Delphox @ Air Balloon
Ability Blaze
Timid Nature (+Spe, -Atk)
252Spe 252Sp.A 4HP
Skill Swap - Psychic - Psyshock - Flamethrower
Delphox is here to cover against Mega Metagross and Mega Venusaur. Skill Swap to mess with Mega Kang and others, though Magic Coat works helps out more when Prankster users show up. Doubled down on Psychic moves so I can nail any non-resistant opponent in the appropriate defensive stat.
Lopunny @ Lopunnite
Ability Cute Charm
Jolly Nature (+Spe, -Sp.A)
252Spe 252Atk 4HP
Fake Out - Ice Punch - High Jump Kick - Thunder Wave
And finally, my star player Mega Lopunny. High Jump Kick NUKES EVERYTHING. Ice Punch for coverage. Thunder Wave for control and to setup for Mismagius.
First off, I really urge you to replace Archeops, it's ability is really, really, really BAD. 50% Atk drop when it reaches 50% HP? Why do you want that, you can't keep it over 50% all the time. Like apocalypseArisen suggested I would go with Aerodactyl to.
Aerodactyl @ Aerodactylite
Nature - Jolly
Ability - Pressure
220 HP / 52 Atk / 4 Def / 4 SpD / 228 Spe
- Rock Slide
- Sky Drop
- Roost/Ice Fang
- Protect
Or if you don't want to use 2 mega's you can go for this:
Aerodactyl @ Lum Berry
Nature - Jolly
Ability - Pressure
EV's - 4 HP / 252 Atk / 252 Spe
- Rock Slide
- Sky Drop
- Taunt/Tail Wind
- Wide Guard
Why the Assault Vest on Mismagius? What will it survive with it, Hex is usefull in some situtions, but not recommended in doubles. I use a Mismagius on my team to, but only because I could not use another poison type on my team (Gengar). Why do you choose Mismagius over Gengar? Gengar outclasses it by Speed and Special Attack.
But if you insist:
Mismagius @ Focus Sash
Nature - Timid
Ability - Levitate
EV's - 4 HP / 252 SpA / 252 Spe
- Shadow Ball
- Will-o-Wisp
- Icy Wind
- Protect
Why Heliolisk?
Hyper Beam is a big NO NO in doubles, it's just a sitting duck after he has used it.
Crobat is fine, just be carefull with Prankster Taunt. Talonflame is a good option to, as it can revenge kill with priority Brave Bird. However if you are not afraid off anything Crobat's speed will be enough.
Talonflame @ Life Orb
Nature - Adamant
Ability - Gale wings
EV's - 84 HP / 252 Atk / 172 Spe
- Brave Bird
- Overheat / Flare Blitz
- Tailwind
- Quick Guard / Protect / Taunt
Delphox surprises me a lot. But double stab is not necessery, I would go with something like this.
Delphox @ Expert belt
Nature - Timid
Ability - Blaze
EV's 52 HP / 196 SpA / 8 SpD / 252 Spe
- Flamethrower
- Psychic
- Hidden Power Grass / Grass Knot
- Protect
Like PlatinumDude suggested Lopunny doesn't need speed control her self. It's doubles so her team mates can do that for her, she is fast as hell anyway.
High Jump Kick sure hits like a truck but do you really want to risk it with so many Protect users in the VGC Meta Game?
Lopunny @ Lopunnite
Ability - Limber
Nature - Jolly
EV's - 252 Spe / 252 Atk / 4HP
- Fake Out
- Return / Ice Punch
- High Jump Kick / Low Kick
- Protect / Encore
Hope I was helpfull.