Hi everyone, I'm back from a bit of a break and to tear the band-aid off, I have decided to discontinue this project.
I have tried for a while to work out a way to manufacture smaller batches of this project, but it just isn't feasible on such a scale. Prices for smaller batches would push the price up nearly to what you can get a pre-made Decawave module for.
I was also working on tweaking the hardware to support passive time of flight (no communication required between node and client, just one way signals from the nodes). This would have allowed a more scalable and faster system at the cost of slightly lower accuracy. Unfortunately the Atmel AT86RF233 time of flight measurement module is both documented poorly and doesn't seem to work at all through testing. And with the release of this sort of functionality on the Decawave modules, it just doesn't make sense to continue with the Atmel hardware.
Having said that, I have a completely new and exciting project coming up soon.
It's certainly been a fun ride with a lot learnt. I thank everyone for their support throughout this project.