I don't know, it seems like battery tech is plateauing. I think there's going to have to be a MAJOR breakthough to see any significant improvement from the battery side, like a total game changing discovery. I think the only way you'll get improved battery life in the relative short term is increased efficiencies on the power consumption side of the equation.

I'm certainly no expert though.

Edit: I re-read what you wrote. You seem to think that increases in battery life will come from the power consumptions side as well. My bad :)