I couldn't resist adding some features to Shellicious. You can now run shell commands either asynchronously (as before) or synchronously, like so:

Private WithEvents _s As New Shell
Private _IsExecutionComplete As Boolean = False
Public Sub Main()
 _s.UseNewThread = True
_s.Execute("C:LongRunningConsoleApp.exe")
Do While Not _IsExecutionComplete
'-- do other work here..
Thread.Sleep(20)
Loop
Console.WriteLine("Exiting Sub Main()..")
Console.ReadLine()
End Sub
Private Sub OutputLine(ByVal LineText As String) Handles _s.OutputLine
Console.WriteLine(LineText)
End Sub
Private Sub ExecutionComplete(ByVal TimedOut As Boolean) _
Handles _s.ExecutionComplete
_IsExecutionComplete = True
Console.WriteLine("execution complete; did we time out? " & TimedOut)
If _s.ExitCode <> 0 Then
Console.WriteLine(_s.Error)
End If
Console.WriteLine(_s.ExecutionTime)
Console.WriteLine(_s.ExitCode)
End Sub

I updated the code in the original post. And this time I remembered to give the threads names, which always helps in debugging:

The thread 'ShellErrorThread' (0xca4) has exited with code 0 (0x0).
The thread 'ShellOutputThread' (0x934) has exited with code 0 (0x0).
The thread 'ShellLaunchThread' (0x5c0) has exited with code 0 (0x0).

So far so good. The synchronous behavior respects the same .MaximumWaitSeconds property as before, and there's a new .CancelExecution method if you want to bail out on demand.