Sean Kristafor has created Black Insomnia.
According to guidelines, this is the world's strongest coffee. Depending on how you brew it, Black Insomnia is twice as strong as Starbuck's Dark Roast and packs about 702 mg of caffeine. (The FDA recommends a daily dose of only 400 mg. So for the same amount of coffee you're getting twice the caffeine!
It's now available on Amazon and Kristafor says they've already sold 5-6 tons of coffee. Beware though, there have been reports of heart palpitations after more than one cup, this stuff is so strong.