Hi MythMaker,
My son - who is 16 now - has built 2 original design pinball machines and 1 video arcade machine. I have helped him with the artwork for these 3 projects.
We have used Game On Grafix: https://www.gameongrafix.com on 3 separate occasions now for the exterior vinyl on our cabinets. They have a $149 package for "pinball side and front art" - under the "Customer Designed" menu tab. We have not done any playfield art to date - so I can't comment on that aspect.
My son's first project was done when he was 10 - so that particular finish is going on 6 years now, and for all I can tell, is still as vibrant today as it was then and shows no evidence of peeling free of the cabinet.
Our prep involved 3 coats of the "OneShot" brand sign painters enamel (applied with a roller) - lightly sanded between coats and then lightly finish sanded with a few different grits - don't remember off the top of my head, but we probably wet sanded at the final time with 1500 grit or some such... then used a dry paper towel and tack cloth to make sure no grit remained on the surface. The vinyl has a paper backing which you peel off to expose the adhesive. As these were rather large surfaces, it was a two-man job. We worked out a system where one of us would slowly pull the backing off while the other would press the newly exposed vinyl to the paint with a paper towel held in his hand. (slides better than a sweaty palm)
If I recall - Game On Grafix actually has the detailed instructions that we followed on their website - so you might check there...
I would post a few pictures - but I'm hoping to do a very special post in the near future on our latest projects, and I don't want to scoop it quite yet.
So, that's what we've done - but I would be very curious to hear what others have done - especially since we have not ventured into the playfield art portion of thing yet...
All the best,
Mark