I haven't been following pinball much lately, so for what that is worth.

But has anything besides "testing" happened with this direct ink thing yet in the past several years of poking at it?
You're still collecting art. I guess art has to be done before it gets printed. But does that mean you not received any workable, finished art packages from anybody yet?
Seems like Space Shuttle and Sorcerer (your two project titles from the very earliest days) should be wrapped up for sure. Seems like they should have been wrapped up some time ago actually.
I'm not complaining really, despite what may appear to be me stepping on a land mine maybe. It just seems that FOCUS might be the winning term of the day. In terms of completing a project, jumping around and letting yourself get distracted at every turn hasn't worked out for me ever. YMMV.

Anyways. Good luck with the efforts. Stay focused if you can. It would indeed be a good service for pinball enthusiasts if it ever gets some legs.