Theophilus Chin, a fellow car chopper (http://www.theophiluschin.com), did up a rendering a few months back based on earlier Malibu spy shots and some leaked patent drawings.
his original rendering
I think he did a great job but the rear end was too recognizable as having been frankenstein'd from Camaro bits. I wanted to expand upon his rendering a little based on the newly released spy shots this week. I wanted to fully flush out those crazy tail lights and rump to give a clear idea of what this is going to look like in production trim.
here is my take (tail light changes and other small detail adjustments)