Registered ECC + mATX?

[Tertius Carstens]

I'd like a panacea or whatever is closest. I've looked around, both in this forum and scoured through server boards.

I'd like 64GB+ on an mATX board if that's possible. I.e. lots of cheap RAM for a small space, i.e. U-NAS 810A.

What is the closest that I can get?

 

[artlessknave]

I have 2 of these. one of them is even in a U-NAS 810A (brother's NAS). you can see both builds in my sig.
https://www.supermicro.com/en/products/motherboard/X11SSM