The vim72.diff file is patch to enable level-dependent fold 
highlighting in Vim7.2.446.  This patch isn't absolutely necessary,
but without it the folded headlines will all be the same color.
You can see what it looks like with different colors in one of 
the videos, linked below.  The patch is currently an ugly hack, but
it's very simple and should be able to be made into something that
can be incorporated into the Vim core by someone (unlike me) who 
knows how to program in C.

The project isn't quite ready for primetime, but there are some 
videos illustrating it at http://vimeo.com/user5149406/videos.
I am making rapid progress. . . .