Considering 'in bed under tonneau cover' box. ideas?

I'm expecting to receive a GFC soon. I already have a homemade drawer system. But, I'm going to do some modifications to the system. It works great but it needs some things fixed and I want to modify because it will be easier to reach into the bed from the sides with the GFC (vs. my current canopy).

I'm considering putting a top access box in the front of the bed (next to the cab). I can build one out of plywood and put a lock on it. But it seems like it would be a lot more secure if I could find a metal one.

KB Voodoo has these (http://www.kbvoodoo.com/shop/two-drawer-locking-toolbox-for-tonneau-covers) but they're drawers.

I'll probably just build one out of plywood but I thought I would post up here to see if anyone has found something better.

I see that a few guys have used an old Ranger model that seems to fit but I'm not crazy about that one either.