[Haskell-cafe] WANTED: grey line layout boxes in vim and emacs

I'd like some more help from the editors in getting 2d layout right without trying. Here's a mockup of vim with vertical grey bars delimiting layout: http://www.cse.unsw.edu.au/~dons/tmp/haskell+boxes.png Does anyone know how to get this effect in vim (or emacs)? Bonus points if the grey bars are draggable, changing the indenting. More bonus points for box-based navigation. -- Don