An IDEAL development environment

I've spent a good part of my life thinking about software tools, and the last four months doing a deep dive into the new generation of web tools. And I think I know what I want to build. So here goes.

First: I want to start with the smallest core I can.
Second: I want to be able to build all extensions using the tools themselves.
Third: I want to have the tools mange the process of extension building. That is, I want to be able to describe a unit of work (which may involve changes to various parts of the code base) in one place; that one place will include relevant documentation, as well as code. It will also include tests and other metadata as I figure it out.

After surveying the field I've made the following design decisions:

• The UI will be browser-based
• The development framework will be built on Brunch, which includes
• NodeJS
• Which includes NPM
• Coffeescript
• Backbone, which includes
• Express
• Underscore
• LESS/SASS/Stylus
• Jade/eco/Handlebars/mustache
• JQuery and JQueryUI

Why this combination? As we'll see, it provides a framework that support some important ideas that I have about programming. I want:

• A simple client/server architecture with an easy way to change both sides. NodeJS gives me that
• An expressive notation for my code that makes it easy for me to create Domain Specific Languages for my tasks. Coffee does that
• Simple, expressive notation for markup with jade or  Source HTML clutters my screen (and my mind) with unnecessary characters and constructs.  Jade/eco/Handlebars/mustache handle that.
• Simple, expressive notation for presentation style. CSS is great but it clutters my screen. LESS/SASS/Stylus get around that 
• A sensible predetermined directory structure for my application. Brunch does that