Via this New Scientist story ("Free apps eat up your phone battery just sending ads"), I came to the site of Abhinav Pathak, a PhDer at Purdue. He's been working on energy usage in mobile devices (a topic dear to my heart) building tools to measure the energy usage characteristics of Windows Mobile and Android devices, and thereby model the energy performance of apps. Very interesting stuff; I'd been looking for something similar last year without success.
His 2011 paper presents the modelling side of things. He has two more recent papers listed on his site which don't seem available just yet, and Google Scholar fails to turn them up too. Looks like we'll have to wait until they're presented?