Like everyone said, it seems pretty pointless. I mean, just look, we pretty much have a very large one as is. If i were to do this, i'd just have something made.
You can do a C piller bar, that's a way to feel better about your rear tied in. It will not do more than be shinny and a danger to backseat passengers.
What you can do if you don't mind loosing access to the trunk. Get some sheetmetal and cut it to fit the access hole. Weld that up. It's the "Ikea" brace. It should work. And it's ugly but never seen.
Sidenote: We don't own civic hatchbacks. Mod accordingly.