The drives can only put in another unit of the same model number. Finding a unit with or without drives is really up to you. I would do a google shopping search or search ebay and see what you can find. Yes, the unit is discontinued. There are more data recovery options though. If you are running in RAID 1 then you can remove one of the drives and plug it into a machine to try and get to the data. You can use Windows with an app called UFS explorer or use Linux to get to the data.
