This will do the trick. Coca-Cola Coffee Plus combines two already caffeinated drinks to give you an even more caffeinated concoction with 50% more caffeine.. that's a lot of caffeine.
Haven't tried it for myself but apparently it doesn't really smell like coke, or coffee for that matter, but rather odd. And it sort of tastes like coke but has a coffee aftertaste.
If you're sold on the idea, unfortunately you won't be able to try this anytime soon as the Coca-Cola Coffee Plus is currently only sold in certain vending machines in Japan.
And if you are in need of that much coffee, can I suggest a double shot espresso or two?