I have googled as much as I can, but do not find a lot. The P45 achromatic has been around for some time and I have not read or heard anything about a 'new achromatic' anywhere! Imagine an IQ180 or Credo80 achromatic!
I for one think it is great with the introduction of the Leica M B&W. Hopefully that means the concept is not forgotten.
If everything was up to me (which ofcourse it isn't) then I would choose a modern, big, achromatic back and never look back. Imagine the image quality of an achromatic 80mp back and at the same time no worries about colour casts A dream!
Do you think the achromatic concept is going to continue and get updated or has it already died?
By the way, have you ever seen a used achromatic back for sale. I havn't.