This was disappointing. It may well be that the 27" iMac is gone forever. 24" is too tiny for any professional use and (for me) to equal my 64GB/2TB (last gen Intel) iMac configuration for a replacement - the only option is the Mac $tudio. (unless I don't really need 64GB - and only a small internal SSD to keep MacOS on - and use external SSDs as work space and more externals as redundant archival space.
I'd consider a 24" iMac with an extra 27" monitor if it was 64GB/2TB - but the memory maxes out at 24MB. How strange!!!!