Someone over at the www.arcadecontrols.com forum was kind enough to send me some scans of the Mario Bros. control panel overlay that were high quality. I had to piece the 4 scans together and fix the color differentiation between the pieces, but I think it turned out good. You can check out the image here
The next step with that is to modify the image to allow for my 6-button setup instead of just the 1-button setup.
I now have all the artwork images I need to apply to the cabinet. I just need to get them printed.