I've seen marbles screen-printed with pictures of the Earth from space at a couple of places, and been very impressed. But there are eight other planets out there, plus half a dozen major moons, that would look very good on marbles.
Is this the sort of place where I could ask how much it might cost to get marbles screen-printed with images I provide, and what sort of minimum batch size is sensible? I imagine there's a market for a few hundred in each design per year at science-fiction conventions, and conceivably up to two orders of magnitude more as attractive objects to sell at museums if the price is right and museum buyers can be convinced.
But I have no idea who would produce this kind of thing, and I have no idea if the sane batch size is 100 or 10,000, or if the per-batch set-up cost is $300 or $30,000; the only figure I have is that the Earth marbles I purchased, which were perhaps 2cm in diameter, cost around ten dollars. But I suspect they were produced by NASA, who are more prepared to buy in bulk than I am.
I'd be interested in marbles of 2cm, 2.5cm and 3cm diameters; yes, 3cm is huge, but so is Jupiter.
Tom