The KMAC happy was THE SH** but it was a groupbuy so I highly doubt that it will be available
There might be some people over on this side that want to sell theirs, but international shipping might be an issue for them. I can look it up for you, but I'm not seeing anyone currently.
for now all you have left is acrylic cases because the aluminum cases are all gone. You can try out the winkeyless.kr pcbs, I think they're compatible with the hhkb layout, or you can go with the aliexpress kit that you mentioned earlier.
but no, sadly, you have no other options currently. I'll post something if there is a potential seller for the KMAC happy.