While there is a BA, I have a Pokemon that also fits your criteria. Also, to prevent a PokemonDB uproar, don't switch BA if you like mine better. Don't even Upvote. Just take the knowledge.
I reccomend Salamence. While Garchomp is bulkier, Salamence has higher Attack (135>130) and higher Sp.Attack (110>80). This makes him an awesome Mixed Attacker.
Garchomp is a tiny bit faster (102>100), but one big thing Salamence has is Dragon Dance, which fixes this tiny problem and boosts that already crazy Attack.
You can choose Moxie to turn him into a Sweeper, or Intimidate to bulk him up a bit more. Use Moxie.
It can learn Earthquake and has access to powerful Fire moves: Flamethrower, Fire Blast, and Heat Wave.
Dragon moves? Dragon Claw, Outrage, Dual Chop(If you a gangsta), Draco Meteor, Dragon Pulse, Dragon Rush, Dragon Tail (for phazing out). Pick your poison.
Salamence (M) @ Life Orb
EVs: 80 Atk / 252 SAtk / 176 Spd
Naive Nature (+Spd, -SDef)
- Dragon Dance
- Outrage/ Dragon Claw
- Fire Blast