I am the Director of the ARM Research Center at the University of Michigan. It is a group of faculty and students engaged in all aspects of research into low power computer systems.

News of a recent prototype of ours can be found on page 2 of the following article in the Register  http://www.theregister.co.uk/2012/02/24/3d_chips/ . It is a many-core low power system built using 3D die stacking. For the technical paper see [PDF]