Brian Niemeier, Bradford C. Walker, and myself each have novels about mecha out. Brian has Combat Frame Xseed, now on its third installment. Brad has Reavers of the Void, the first installment of his Star Knight series. And finally, I have Shining Tomorrow Volume 1: Shadow Heart.
What’s interesting about each of these is that each one inverts the basic premise of a well-known sci-fi property. While the stories generally bear no resemblance, the settings in particular act as photo negatives of properties that have far more spread.