hi,
You mentioned…
“I tried many different ways to recover the data, either through Linux or Windows apps that can apparently read linux drives (like the MBL), but all to no avail.”
and did not work, getting the same hardware and replacing the hard drive will not work as well. Chances are there is an issue within the hard drive, or OS is corrupted. Getting a new NAS and replacing the drive would work when there are issues with the enclosure vs the hard drive.
Not sure what guide you followed, as there are plenty of different ways to achieve the same, but if you followed the unbrick guide such as this one: http://community.wd.com/t5/My-Book-Live/GUIDE-How-to-unbrick-a-totally-dead-MBL/td-p/435724 and could not read the files or mount the drive, there will not be any DIY options.
Also, might be a bit too late now, but for any important data, make sure you always have a backup.
http://www.cnet.com/how-to/digital-storage-basics-part-3-backup-vs-redundancy/
