dtcss - Google Code
http://code.google.com/p/dtcss/

good for dynamic css, can conditionally point to different php scripts. reduces editing time for multiple selectors.  good for maintaining!

DtCSS is a PHP script that preprocesses your CSS file. It speeds up CSS coding by extending the features to CSS. Such as nested selectors, color mixing and more. DtCSS reads the CSS file with special syntax written for DtCSS, and outputs the standard CSS. It also comes with a smart caching system.

Seems like an interesting idea. Wonder if it could be incorporated into EE...