The example your referencing is most likely a Render to Texture technique. (Notice the fish eye-lens effect of the display to simulate a bulged CRT monitor. It's most likely accomplished by what's known as a Shader.) Now if you mean like a Command prompt in a GUI, there is a way to "fake" it. Insofar as actually embedding a command prompt within a Window, i'm not sure if that's possible.
Basically you would make a sub-window, make it look like a console window, and then you would redirect console commands to this sub-window. (incidentally I did something like this in Java recently with Swing) There is documentation for this for Win32. But, you use QT so another member may be a bit more help there.
Here's a MSDN article for retrieving, and redirecting a handle to stdIn, out, and error. Take a gander, and don't let the ugly code sway you either way since this is for Win32, not QT. But, I can't imagine the overall flow would be terribly different (of course i've never used QT so who knows)