Saw this in my most recent Diesel Power magazine. Go to
www.facebook.com/generalmotors - there is a page devoted to discussing the potential 4.5L diesel for light duty trucks.
(Of course, I saw an article, too, where someone actually stuffed a Cummins ISB into a chevy s-10 pickup. I always wanted to put a sb350 into my Jimmy, but never thought of an ISB in there!)