I'm going to head into to building one of these, then build a couple more if it works well. I'll be building a Pi Zero W to 2413U as I think that will be the easiest for others. Will probably do a solder and non-solder version, but leave the "use ISY power instead of wallwart" to those who want to read this thread.
I plan to add to the instructions so we have a single page with links to products, etc. so that anyone can build by just going to that page. The idea would be a specific recipe with software ready. You buy these parts, build this way, install this software, run these tests, etc. I"m considering doing the image/config work as well (for Pi Zero W) and detailed build instructions for other pi's. It appears we'll need a custom kernel for fast boot. I haven't played with Pi OS before but it doesn't look hard to figure out. if anyone has already done the image work or install/config beyond the install.sh mentioned in the thread, please let me know.
In terms of contributing content, should I use the github project? Any other pointers so I don't duplicate work would be helpful. I'll report back (it may take me a while to get to it).