Hello everyone!
I took some time to check things over last night, as well as to look into cost. It looks like I'll be able to do a set of boards (a single channel involves a main board and three auxiliary pcbs) for $20 USD, and that could even come down a bit depending on how many folks join in. To keep the cost down, I will only have the main board manufactured with the ENIG gold plated finish (essential for the 500-series backplane connector), but will have the aux boards done with HASL, which is less expensive and likely what you're already accustomed to seeing on your PCBs. Otherwise the cost nearly doubles, rather needlessly in my humble opinion.
I will need to get shipping estimates once I have a sense of where I will be sending boards. For reference, the cost to ship boards to Ian in the UK and Herbert in Austria came out to ~$45 USD in each case. Shipping within the States will obviously be less, and shipping elsewhere in the world might be the same or more. This was the least expensive option I could find, but since I know we have members here who have more experience shipping things internationally, I'd be open to any pearls of wisdom you might have!
So I guess this is it! I will start taking names of those who would like to purchase PCBs. For now, I'm going to limit this to a single run of boards. I do not know if this is something I will do more than once, so if you have the interest and the means, please heed that disclaimer. Send me a PM or leave a post below expressing your interest and how many sets of boards you'd like to have. I'll keep it open for two weeks (ending April 10th), at which point I'll finalize the list and we can move forward with next steps!