Originally 42V systems were going to be adopted this year but they decided to push it back a little while longer. The reason for 42V systems is a good one. The higher the voltage that is used, the lower the current that is necessary to power accessories. Therefore if we switch to higher voltage systems they can use smaller gauge wires to carry the power since they don't need to pass as much current through them. If you've ever seen some of the wiring harnesses behind the dash of a fully loaded luxury vehicle you can see why we need to do this, those hundreds of wires take up a lot of space and there relativly heavy. If a manufacturer can remove 10 pounds of wires from there vehicles and gain .10 mpg, it might not seem like much, but to them it is a big deal. I think some high end foreign luxury cars are already using 42V systems and all the Hybrid cars are using 288V electrical systems, at least for the drive motors.
-Jon