So... It's just to hold the drives?? And you'll use a usb cable from each drive to the computer you want it in???
You can get JBOD enclosures. JBOD means just a bunch of disks.. where a NAS will give you a console or gui to manage disks and things like raid, a jbod enclosure would act the same as an external usb drive... Even with multiple disks. Though this would only be for one computer..