Nah, window. The process is easily visible in ps/tasklist. 
Getting AV bypass here was the easy part once i figured out i could call PSH with R3dy's psexec cmd module (still working on the WMI path).
Getting eyeball bypass is a lot harder. Powershell insists on making itself clearly visible, even when run as system. If you strip out all of the hiding flags, you'll get these awesome prompts in a user session about a task requiring your attention in session 0 (formerly admin console pre2k8). If you follow the prompt it will actually load you into the empty desktop session of system where a powershell window exists. PSH really likes its windows.