It appears the project hasn't optimized for production (yet?). For now, I can't help but think it may be possible to cobble together a Sprig using inexpensive Pi Pico HATs and 3D printing. Here's the schematic:
Yeah, I'm sure it could. But even being able to buy a fabbed board (it's all through-hole components) would move things along. And I find the non-optimization pretty endearing, since it enhances the approachability and ability to understand the whole system.