I do something related; I extend sass with a few custom functions which allow a convenient way to build svg from specifications written directly into the sass.

I do something related; I extend sass with a few custom functions which allow a convenient way to build svg from specifications written directly into the sass. Specifically I use it to build svg filters which are intimately related to the css rules which apply them. It's very useful to have both the css and svg produced in the same pass by the same tool. I haven't done it, but this system would probably also be useful for using CSS to animate SVG