Are there any off the shelf e-readers which support this firmware? This site seems to be for people who want to solder together their own e-reader from components.

Also, it does a bit misleading to say "Charging, battery protection, an optional frontlight and a 24-pin e-paper interface, all on one PCB you can build for around $60." According to their own parts lists, if you are build 5 of these, you're in for $63.74 (plus shipping?) So if you want just one (like a normal person), it's going to cost more. And that's still just the circuit board and components: no mention of the outer plastic casing. (I can't find any info on their site about how to get that - presumably 3D print, but haven't found plans.)