I'm not sure why I didn't think to look this company up before. My wife has this Nifty Cargo Liner with Cargo Loks for the back of her KIA Soul, and they are awesome. The cargo liner is made from rubber that is covered with a carpet, and has a lip to hold in liquids. The Cargo Locks are these "L" shaped things that velcro to the carpet to help hold things from sliding around, and they work great.
So I looked them up this morning and bummer, not only do they not make products for the Z, but they don't even list the 370Z as an option to choose from.
Anyway, I just sent them an e-mail this morning asking them if they could makes something custom and how much that would cost, or what it would take to mass produce it for the Z. With any luck we'll get a positive answer.
Nifty Cargo Logic Cargo Management