Wheelhouse CMS is a project I've been working on for a couple of years now (way too long for a first release, I know), which I've bootstrapped whilst freelancing building content-managed web sites. Many iterations and hundreds of private gem releases later, I'm finally confident enough to publicly release version 1.0.
You can check out a demo directly at http://demo.wheelhousecms.com/admin.
I'd love to hear what you think and what can be improved.