You just have to look at the code behind this - http://nicolasgallagher.com/pure-css-gui-icons/demo/ - for confirmation that this is not a viable solution for complex shape creation.

I'm in the midst of reading Robert Bringhurst's Elements of Typographic Style and it's really motivating me to design my blog in a lot neater, cleaner, typographically-aware style. I think you've really nailed that. If you haven't read that book yet, I highly recommend it; I think you'd appreciate it.