Marty Lists brings us ShellExecute, a freeware application that is similar to the built-in START command, but in addition to normal, minimized, and maximized, you can also launch applications as hidden.

The readme contains:

Shell Execute \[version 1.00\]                              Launches executables or documents according to their file type association.                              The syntax of this command is:                              ShellExecute.exe /F:file \[/P:parameters /W:workingdir /R:runstyle /A:action\]                               /F:	Specifies the file to execute.                               /P:	Defines the command-line parameters to pass to the executable.                               /W:	Defines the working directory the executable starts with.                               /R:	Defines the window state, default is normal. (/r:Min|Max|Hidden).                               /A:	Defines the action to take, default is Open (Print, Explore, etc.)                              Examples:                              ShellExecute.exe /f:D:\\Setup.exe /p:-S -SMS /r:hidden                              ShellExecute.exe /f:C:\\Boot.ini /a:print                              An argument of /? displays this syntax and returns 1.                              A successful completion will return 0.                              Copyright 2001 Marty List