Good news for those wanting to build out a custom Arm64 desktop:
ASRock Rack has a mobo+Ampere CPU combo that restocks every few weeks on Newegg: https://newegg.com/p/N82E16813140134
And Noctua's prototyping two new LGA 4926 coolers (pictured: NH-D9 AMP-4926 4U)
I am building out my 45Drives HL15 server with this board and will hopefully have a video up on it soon!
Full review will take longer though—need to test out software, get an idea of power draw, test performance/networking... but so far so good!