I started to attempt a repair on my rust-laden car using the wonderful Bondo polyester based filler putty. (at least I think that's what it's made of) Let me tell you, that stuff has some serious fumes. Nevermind the fact that it contains carcinogens...
At any rate, I did a very messy, ugly, and unprofessional job on the rear wheel well. When I realized that the Bondo was not going to fill in the large hole above the wheel, I cut a strip of aluminum flashing, stuck it to the Bondo over the hole, and slathered on some more to make it stick. (I can see auto body specialists cringe right now...) As far as I know, I don't think there's a law that says you have to do the repair correctly -- just as long as every hole is covered with something other than duct tape, I should be fine for the inspection, right? sure.
But hey, don't knock aluminum flashing (no, seriously, don't knock it. it'll deform quicker than you can say "crappy repair"). Although it's basically one step up from tin foil, it has held up surprisingly well on the front driver's side quarter panel where I fastened it with duct tape. In fact, it's so easy to work with and durable, I'll probably use it on that same panel tomorrow when I attempt to repair the ~6 inch hole, but I'll probably use a 2-ply solution to increase strength. who needs sheet metal? Not me.
It'll be a tricky fix. I don't have pop rivets (whatever those are...) or sheet metal, so I might just slap the flashing on there and secure it with liberal amounts of Bondo. Then it'll be as good as new!