I used gimp and downloaded pacmaze from the arcadeartlibrary a fair old chunk of editing and I had something I was happy with.
It would probably be fairly easy for you to edit as the original art is designed for a full sized cabinet

As for the artwork, OK the first thing you will want to do is draw the cab to scale. Take the measurements in Inches, hardest bit will be any angles etc. (I drew mine as a rectangle first and then using measurements from where angles start and end etc was able to use guide lines to remove the bits that I didn't need) To make things slightly easier I created the template for mine in gimp at 100DPI My cab is approx 30" x 24" which came out at 2400 x 3000 (Give or take). (You would then scale that image up to 300DPI) this would give you an image of aprox 7200 x 9000 (if machine was same size as mine then this would be fairly close to the real size of the machine. You will probably want to make it slightly bigger to allow for bleed. Whatever you do, do not do what I did and do all the edits at 100DPI and then scale art up to 300, Unless you want a slightly blurred artwork. To keep it sharp you want to use 300 DPI for the artwork from the off.
You could take this template and have it printed out on many sheets of A4 stick them together and then put on side of machine, make edits accordingly, rinse and repeat until the template is perfect.
Alternatively create the machine template to exact size at 100dpi and use that as the template to cut the wood, voila artwork guaranteed to fit.
Attached the pacman vector I modified using Inkscape and Gimp.