I generally have used the sshd that comes with Cygwin, which is bog standard OpenSSH and works quite well. OTOH, it assumes Bash for its shell, and while you may be able to spawn PowerShell automagically, I don't think that's what you're suggesting.
Certainly seems that somebody ought to have done this already....
It’s intended to be managed with Powershell, which I think means from a Powershell session on the local machine. From there you can open an interactive Powershell session on the remote machine with Enter-PSSession.
BTW, since PS itself runs as a bog-std Win32 console app (the difference: fancy colours/type when invoked by itself), I think it would be nothing more than setting up a shell script/batch file that spawns PS at startup...
This is PowerShell running from the Korn Shell/UWIN (by Southwestern Bell)
Which means that a shell script executed at startup, should be all that is needed to spawn PS from an OpenSSH session...