Hi jwr,
co-founder of paddi91 here. What your are saying is essentially what has driven us to start investigating into this.
We come from the Open source hardware and hobby electronics world, and have backgrounds in mechanical engineering and information technology. So we wondered how we can add a European flavor to it:
Lots of high quality manufacturers here in (central) Europe, but with a focus on High-End High-Scale series production, both for PCB and PCB assembly. We collaborate with them, automate most of the production process for them, and thus are able to offer competitive prices for low quantities.
We started investigating into this because we want every OSHW project to be reproducible by others. So that if you are an author and publish your designs with us (we synchronize with github if you want), other people (and the many others that are not able to design or assemble the project) can receive a copy of the current version. And since not everyone can assemble by themselves, we try to make it as simple as possible which is the reason for the PCB Assembly pilot. Here we use similar tools to automate everything. It should therefore be affordable to re-produce any project on-demand. Seriously, if you want to help make open source electronics more accessible come and join us with your project for the assembly beta, the more projects, the better, as it improves the test-suite ;-) feel free to either send an email to patrick via patrick@aisler.net (my co-founder) or contact me directly via felix@aisler.net
By the way: the cost parameters for assembly would be the following:
cost of the pcb x 2 + cost of parts. no minimum quantity required.
All boards come with green soldermask, white top and bottom legend, and will have ENIG surface plating. We only use high-class FR4, 1.6mm TG150 material.