Quoted from Richthofen:
Those photoshop files are of incredible value. It would be nice to build a database of artwork files (cabinet stencils, playfields, plastics) and host it somewhere on the internet so people could get them printed themselves. I think you'd be ok as long as you gave the files away. Not sure though.
I'm sure you would get "the letter" from Gottlieb or someone about copyrighted material.
There has been talk lately of anonymously uploading manuals, schematics and artwork to the technical e-book newsgroup: