I don't have any pics and haven't installed it yet, but I built a gas tank skid a while back out of some free 3/16 steel diamond plate. It's going to bolt onto the two rear bolts of my hidden hitch and im bolting some mounting brackets to the frame rails just in front of the tank on both sides. It wraps from in front of the tank, about 2 inches up, to behind the bar of the hitch. It's definitely solid and I'll post pics once I can get them.
Now I'm just thinking I should have waited and gotten some smooth stock instead. I'm worried that the diamond plate, while looking bad-a** will have too much drag. Any thoughts would be good for me and anyone looking to build their own soon! Terry's is smooth and also gets rid of drainage issues by having it open on the front. Since mine has the lip on the front, I left the bottoms of the sides open.
To weld mine I tacked every three inches or so, then came back through once the whole skid was tacked and filled in between the tacks, working from one side of the skid to the other so that one side wouldn't overheat and they would have time to cool before I bot back to where I had just welded. It worked well for me.