Maybe they kept it closed and limited run for the first batch so it would be easier to source parts to populate them. I don't know if it needs a specific revision of Agnus or Denise but it does need the QFN style CIAs, and does it need a Buster chip? The A1k 500 Reds will have probably reduced available parts as converter boards where made to make QFN CIAs in DIP modules (Paula and Denise too IIRC). Also it's always a good idea to keep a first production batch small in case there are unexpected problems.
There was a URL for a website that will be dedicated to the project posted on FB but it's wasn't up yet.
Designing an new A500 motherboard isn't that hard, the schematics have always been available. This one has some nice mods included like Zorro connectors and PS2 mouse and keyboard connectors all fairly straight forward. The RGB connector has been changed to a 15 pin which is a sensible decision.
