Eh, it's not a "giving a copy to everyone" kind of thing, it is more of a "preservation" type of thing.
Remember, what I brought up was the original Marble Man prototype, with trackballs and more enemies and stuff.
With the public proto we have now, yes, in the past many people were confirmed to have a cabinet and it was confirmed to be preserved and running in MAME.
But from what I know or what I can remember, there isn't a confirmed owner or location of the original Marble Man prototype. Not even Bob Flanagan has the full cabinet, apparently he only has the source code.
All there is online is a single video about it, which I'm pretty sure dates all the way back to 1991, before the cabinet was even put out for public testing.
This cabinet really is lost as of now, and I'm wondering if anything can be done to even see if it still exists. I don't really care about a public release; if I want to play Marble Madness II, I'll play the current version we have in MAME right now.