I put forth the mead argument more as a joke about the way this type of discussion could get very heated, but seriously, there is a good case for the possibility, although it's definitely pure conjecture. Ken Schramm outlines the argument in his book, but the basic idea as I recall is that while we know when humans started cultivating grapes and grains, but there is evidence that honey foraging was practiced much longer before, and, since the discovery of fermentation was likely an accident (as some have hinted here already), the fact that honey was one of the first fermentables that was gathered in a readily workable form (as long as it was added to even a little bit of water...you really don't need to dilute honey all that much to make it fermentable), makes it likely that it could have been the first fermented beverage. The grapes and other fruit would more likely just have been eaten, and while malting could happen by accident on a limited basis, it just adds another step to the chain of "accidents" that would have to occur for humans to discover fermentation, and the joys thereof...