Is there an IDE out there that does structural syntax highlighting?

Question

Somewhat inspired by this question about a graphical programming environment. I don\'t think that C++ or C# are really conducive to this type of environment, but perhaps there\

Answer 1

I'm working on a Visual Studio extension inspired by this question. You can see what I have so far here:

http://lorgonblog.wordpress.com/2010/11/12/the-f-compiler-source-release-making-it-easy-to-write-cool-visual-studio-extensions/