How to switch user from a command line
Is there a command to use the "switch user" feature,
You can connect to an existing session with tscon.
What I'd like to do is get to the "welcome screen",
Use tsdiscon.
If Fast User Switching is on, then simply locking the workstation* should display the Welcome Screen too.
* I hope you don't use rundll32 LockWorkStation.
I believe it is possible, this article from Lifehacker explains how:
runas /user:*computer name\*account name explorer.exe