On average, it takes 2 tablespoons of coffee beans to make a cup of coffee. A cup of coffee, depending on the brewing method, contains 90-150 mg. of caffeine. Eating the coffee beans, as opposed to drinking the coffee, might give you a greater dose of caffeine, and the chocolate coating adds even a bit more caffeine to the mix. As for a chocolate-covered espresso bean, a Shock-a-lots candy and chocolate covered bean is reputed to have 20mg of caffeine per bean. So about 5 beans would give you about the same amount of caffeine as a cup of Joe.
Sounds like a good late night snack before heading off for a good night's sleep to me!
Espresso Coffee Snobs