I'm hoping the Aoostar 6 bay NAS isn't vaporware, but many previous ones have been, in no particular order:

  - wiretrustee NAS
  - pibox 5 bay
  - storaxa 5 bay (scam/company disappeared into the night)

and several that have actually delivered:

  - axzez cm4 NAS
  - U-NAS (case only)