What kind of cost would one be looking at to actually produce chips (like order of magnitude, not asking for a formal quote) ? Imagine, an OSS design, selected for the google shuttle, chips comes back, they work awesomely and now I want to build more.

SkyWater is charging ~$40k for their SKY130 MPW service (emailed them). Would be great for efabless to be able to offer smaller chunks, more economically. Europractice, over on this side of the Atlantic, offers access to nice MPWs for much less (see here).

Yeah $40k is definitely out of my budge, I'd be more looking for something in the 1-5 k$ range ideally.