How to set Windows Services permissions from Powershell?
I think for this you should look into using subinacl.exe which you can download here. From the download it site it is described as:
SubInACL is a command-line tool that enables administrators to obtain security information about files, registry keys, and services, and transfer this information from user to user, from local or global group to group, and from domain to domain.
Using it from PowerShell appears to be pretty easy:
SUBINACL /verbose=1 /service Spooler /grant=PC\Joe=LQSTOPCheck out this article on using subinacl that Mark Minasi wrote..
Cold question deserves a partial answer.
Check out http://get-carbon.org/
If you don't want to install carbon on a production server then look a the source (Apache 2.0 Licence) and see if you can utilise the .NET code for your own devices. If I had time I would expand this answer to include example code but for now see these two parts of the repository.
Powershell CmdLethttps://bitbucket.org/splatteredbits/carbon/src/29f5983094d048030d6143923f4a6925d1a1a195/Carbon/Service/Grant-ServicePermission.ps1?at=default
Uses a .Net object (using system)https://bitbucket.org/splatteredbits/carbon/src/29f5983094d048030d6143923f4a6925d1a1a195/Source/Security/ServiceAccessRights.cs?at=default
From that it should be a hop skip and a jump to write your own Powershell v3+ native call.