There was actually "SUA" after "SFU", only removed in Windows 8.1 and Windows Server 2012 R2.
It was mostly for running NFS to talk to other UNIX boxes, not to run UNIX software.
To make a Windows NT box UNIX-ish, there was MKS Toolkit. It predates Cygwin, msys, and djgpp.
And before they got golden goose with MS-DOS/IBM deal, they were into the UNIX business with Xenix.
A few reasons why Linux would probably never taken off, had Microsoft stayed closer to their UNIX related projects.