LESS – Leaner CSS: This is so necessary. It’s an improved, lighter CSS syntax that you store in your source, with a compile (more like an “expander”) that generates actual CSS for deployment.
Less is Leaner css. Less extends css by adding: variables, mixins, operations and nested rules.
Less uses existing css syntax. This means you can migrate your current .css files to .less in seconds and there is virtually no learning curve.
I could see building this expansion into a build script in Nant or CruiseControl or something.