We've covered a lot of Sass and Compass ground in our time together. At this point in building up the style sheets for http://sassandcompass.com, I feel the Pareto principle is coming into effect; we've covered 80% of the work with 20% of the effort. Rather than enduring the final section (sure to involve me making all manner of tedious mistakes) that wouldn't really offer any insights into using Sass and Compass, I'll be happier for you to simply grab the complete code download from the site itself.
Instead, at this point it will be more instructive to try and circumvent and address any issues we have introduced with all we have already done.
Remember that even with strong Sass and Compass-fu skills, it doesn't prevent human errors being introduced into the code. Therefore, when I feel like a project is around 70-80% styled (conveniently, the place we find ourselves), I like to take a good look at the compiled CSS and clean up all my usual schoolboy errors...