Hi, I investigated some more and found that Win32::AdminMisc::CreateProcessAsUser can start a GUI-program in minimized state:

    use Win32::AdminMisc ;
    my $prog = q(c:\\windows\\notepad.exe);
    my $pid = Win32::AdminMisc::CreateProcessAsUser( $prog,
                                                     Flags   =>  DETAC
+HED_PROCESS,
                                                     Show    =>  SW_MI
+NIMIZE
                                                   );
    if ($pid) {print "Success starting $prog, new pid is $pid";}
    else { print "Failure starting $prog";}
[download]

The "Show"-parameter can take different settings, for instance:
SW_MAXIMIZE - Show app maximized
SW_HIDE - Show app hidden (appears in task manager only)
SW_SHOWNORMAL - Show window in normal state

Check out the documentation for the full list.

A .ppd package for Win32::AdminMisc can be downloaded here

Regards,
ldln