There isn't one, primarily because no-one has ever cared enough to scratch that itch. I, too, would love to have one, but I use a decent one, called HTML.

I guess I would suggest going ahead and defining what you would like that interface to be. Don't write any code - just a design. Then, post it here for comment and suggestions. Don't be afraid to start small - maybe just what you need. People will add to it. Then, if you're lucky, other people (most likely including you) might go ahead and write the connections between what you want as an interface to Tk or other options. Then, you get to add "Inventor of Blub" to your resume and make a million dollars consulting on how to implement it. :-)