:o

I can write such an app.
I used this to hide a command window for the ventrilo server I run

If you know about programming
look into the c++ function
ShowWindow();
as in
ShowWindow((HWND)ventProc»MainWindowHandle.ToPointer(), SW_HIDE);

if you need me to write an application let me know the exe name or the main window name of the application you want to hide.

but doing this means you will have to call a program to hide that program and then possibly call another program when you want to unhide it