Please join the '90's and actually implement PAM as quickly as possible.
It is already part of both MacOS and Linux, and has been around for more than 15 years. PAM is currently supported in the AIX operating system, DragonFly BSD, FreeBSD, HP-UX, Linux, Mac OS X, NetBSD and Solaris. Using PAM would make it far easier to implement SSO (Single Sign-On) in all kinds of interesting ways. Including using Samba credentials to login to the NAS via SSH etc, which would make NAS shell access far more transparent for Windows users to access the NAS.
You have recently added support for "home" folders in your Windows networking, so home folders with "user login" to the NAS, rather than "admin-only" login via SSH would be far easier to implement from various platforms, if PAM was implemented.
Microsoft is unlikely to ever play nice with the Linux world, (note especially their refusal to offer a built-in "SSH" client in Windows, despite SSH existing for over 30 years now), and the changes in default network security settings introduced in Windows 7, which effectively "broke" Windows access to non-Microsoft SMB Servers, with no added benefit to the End-User). With the direction Microsoft seems determined to take Windows in, I'm assuming the number of Linux and Mac users can only continue to grow in the near future.