I would like this as well. I was an early investor into the Windows Home Server market with my HP EX470 (sitting in my closet) and currently running a DIY box with DrivePool. I have a mismatch of drives, and I would love to be able to maintain that and expand based on the best bang-for-the-buck drive at the time.
I fully understand this is a big ask and not a day1, just adding my name to the list if there is further interest. Thanks!