wavetrainSUP - http://www.wavetrainsup.com
is an all CoffeeCup site.
I started with the Animal Shelter theme and evolved it. I guess I'm either more old-fashioned than I thought or dumber than I think I am, BUT I still prefer looking at code. So I went back and forth between RSD and the old school CoffeeCup that I know and LOVE. They're like peanut butter and chocolate. RSD and the themes are an invaluable starting point. The CSS that RSD auto-creates is wondrous, more so, after reading through it.
I need to tweak the breakpoints and ESPECIALLY get images that are optimized for those smaller screens. As with so many other sites, I find that lack of sufficient content is a real showstopper. I am no longer surprised at the number of clients who have no ( or very little) imagery to work with -- of their own products.
Anyway, wavetrainSUP is my toe dip into the water of RSD.