Here are the cars that I had pictures of before, but seen from the middle of the underbelly. What i found interesting was that on the Fusion hybrid, there was not much effort to keep things smooth. Lowering the car and adding a full bellypan decreases the drag quite a bit.
Honda cars seem to have nice flat gas tanks with ridges to perhaps better control the airflow better. ( More likely simply to add rigidity, though I see these ridges used a lot - especially on the front of the CRZ for example )