Looking into the future a little bit...
We are now in the late stage of experimental hardware, with the next step being a real prototype design. Once we have at least one working prototype receiver, the next step we might consider is getting a quote from several places like this:
http://aapcb.com/about-us/
Those quotes should allow us to arrive at a realistic cost estimate for pre-built modules. With that information, and test results from the prototypes, we should be able to create a crowd-funded proposal on a site like this:
https://www.kickstarter.com/
My hope is for there to be pre-built modules that only require connecting a few wires, battery holder, antenna connector and such, but no surface mount assembly required. The modules should come pre-programmed, tested, and aligned. There should either be a 3D-printed chassis available that the modules drop into, or the boards should slip right into an off-the-shelf chassis box.
Even if the cost of the pre-built module approach proves to be too high, or the interest just isn't there to support a production run, everything about this project will still be available publicly for all to use: schematic, BOM, board design, shared OSH Park boards, source code, binaries, assembly instructions, user manual, and support community would all be available to anyone wanting to build the receivers themselves... or to create follow-on product(s) based on the 2-band receiver and/or transmitter designs.
Although simple ARDF receivers can be built, and beginner units from China can be bought relatively inexpensively, competition-grade receivers are difficult to find and expensive to acquire. A single-band ARDF receiver suitable for competition, with no support, no schematic, and no warranty can cost several hundred dollars the last time I checked. I think most who are serious about the sport of ARDF will find this project to be a better alternative... especially if there is little construction involved.