I recently installed an ATM Fender Well cold air intake system (along with many other mods) on my 2015 Fiat 500 Abarth. The top of the engine looks pretty rough without the factory intake system so several manufacturers offer after market engine covers. However, I could not find one which matched up with the ATM fender well system, so I made my own.
I did some CAD (Cardboard Aided Design) work, converted that pattern to a DXF file, and sent that file to SendCutSend.com. They laser cut a piece of .0125" 5052 aluminum and bent the edges for me. I Emailed the file on Monday and I had the completed piece in hand the following Friday at a cost of just over a hundred bucks. That seems really inexpensive to me for a single custom piece and it also seems like very quick service too.
I treated it with Alodine and purchased some wrinkle finish powder from prismaticpowders.com. My friend used his cheap Harbor Freight powder coating gun to apply the finish. I think it came out great.