I\'ve got some experience using haml (+sass) on rails projects. I recently started using them with blueprintcss - the only thing I did was transform blueprint.css into a sass fi
I'm not sure if these resources have only shown up recently, but have you seen the Compass CSS3 helpers and the General utilities - (both well documented in my opinion) - they've really sped up my interface builds a great deal.
Another great resource is the Compass plugins page.
Personally I like to copy these utility Sass files out the rubygem and manually include them in my project's Sass files as it feels pretty weird referencing Sass which is stored out of the project.