Graphical REPLs?

Where are all the Graphical Read Evaluate Print Loop Interfaces? Where is the graphical shell? There was TermKit a bit back, but TermKit relied on Node.JS plus Webkit.. which was a fragile solution. Though, conceptually, TermKit was right on target. But what might the "ideal" graphical REPL look like?

Is a HTML DOM tree styled with CSS adequate to represent any output? Does it make sense to wrap it all in Webkit? How do we hook into files? Or do we need a new way to represent the output of command line applications? A new shell with a new objects system too?

Say we build this Graphical REPL.. Will the line then blur between graphical and command-line-applications? Or are graphical and command line enviroments destined to stay divided?