I can certainly confirm kettlefish's word about HiG Staff's use of excellent English. Everyone I spoke too at Essen were more than fluent!
I'm sorry, I didn't want to come across negatively, as I think your idea is admirable, but many have mentioned the economic issues; from the printer and the the publisher - these are two different organizations.
I'm not aware of the industrial scale of the printers HiG use, but I suspect they wouldn't even turn their printer on for less than a $250k batch. These are the same printers which have printed the ~2-million copies of the base game of Carcassonne that have sold since the new art work was introduced less than 2 years ago. That's the scale of the printer used.
I don't think these guys turn up at work at 9am and print 100 copies of a game in a morning when they're ordered from suppliers. I think it's more likely they create a batch of 10s or 100s of thousands of copies. The publisher has to judge how many copies will sell over a period of time, before starting a new print run. I suspect, given the 16 years of experience HiG have publishing Carcassonne, they can model this very well. They how many and how quickly a print run will sell and when the optimal time to produce, in order to see the return on their investments. HiG are experts in this field.
But back to the printers:
Every print run will require proofing to check the colour and alignment is correct. I suspect the Carcassonne tile printer also feeds directly into a machine that cuts them. Once everything starts the printer will run continuously, day and night until the order is complete.
If you had a printer which could print vast copies of something in a consistent way; would you:
i) Spend time preparing a print run of 100 copies or
ii) Spend the same duration preparing a print run of 100k copies?
The wastage of proofing print runs will be the same.
The printer doesn't care so long as their paid, so the publisher would have to absorb that cost. But the issue is the vast overhead in creating every print run.
From the publisher's perspective - If you had to pick between printing a brand-new expansion no one has, or printing an expansion 98% of the people who-would-ever-buy-it already have, which would you opt for- remember that overhead we have to cover?
I suspect all the Besieger tiles were printed in a single run in 2013. And shared between a panels and included with the Müller Exklusiv-Edition.
Crop Circles (Not Corn Circles as you stated) was issued twice, in only two runs. This is clear because of the differences in green in both copies/editions.
Also the Easter 2016 Cundco Newsletter included:
During the spring cleaning a partner merchant appeared a mysterious small box, on closer inspection, it contained ... drumroll ... 100 mini-expansions "The besiegers'! This rarity we no longer produced and not reissued. But at Easter, we can offer you these 100 copies still, of course, only as long as this same stock. And please: Only once the besiegers per household order, there are as many have a chance.
I admire the passion and work - but I don't comprehend where the the economic incentive HiG would need to print these expansions; unless you're offering to but 100k editions for 10Euros each!
It you need someone to boost the numbers, put me down for a copy of anything produced - but I can't do more than that.
I would have picked you up a copy of BB5 at Essen for 20Euro if I'd known. I suspect there will be some left next year too!